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Author |
Chaves, A.; Covaci, L.; Rakhimov, K.Y.; Farias, G.A.; Peeters, F.M. |
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Title |
Wave-packet dynamics and valley filter in strained graphene |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
82 |
Issue |
20 |
Pages |
205430 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The time evolution of a wave packet in strained graphene is studied within the tight-binding model and continuum model. The effect of an external magnetic field, as well as a strain-induced pseudomagnetic field, on the wave-packet trajectories and zitterbewegung are analyzed. Combining the effects of strain with those of an external magnetic field produces an effective magnetic field which is large in one of the Dirac cones, but can be practically zero in the other. We construct an efficient valley filter, where for a propagating incoming wave packet consisting of momenta around the K and K' Dirac points, the outgoing wave packet exhibits momenta in only one of these Dirac points while the components of the packet that belong to the other Dirac point are reflected due to the Lorentz force. We also found that the zitterbewegung is permanent in time in the presence of either external or strain-induced magnetic fields, but when both the external and strain-induced magnetic fields are present, the zitterbewegung is transient in one of the Dirac cones, whereas in the other cone the wave packet exhibits permanent spatial oscillations. |
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Wos |
000284401600007 |
Publication Date |
2010-11-19 |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
95 |
Open Access |
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Notes |
; This work was financially supported by CNPq under NanoBioEstruturas Contract No. 555183/2005-0, PRONEX/CNPq/FUNCAP, CAPES, the Bilateral program between Flanders and Brazil, the Belgian Science Policy (IAP), and the Flemish Science Foundation (FWO-V1) ; |
Approved |
Most recent IF: 3.836; 2010 IF: 3.774 |
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Call Number |
UA @ lucian @ c:irua:95542 |
Serial |
3905 |
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Permanent link to this record |
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Author |
Chaves, A.; Farias, G.A.; Peeters, F.M.; Szafran, B. |
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Title |
Wave packet dynamics in semiconductor quantum rings of finite width |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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Volume |
80 |
Issue |
12 |
Pages |
125331,1-125331,14 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The time evolution of a wave packet injected into a semiconductor quantum ring is investigated in order to obtain the transmission and reflection probabilities. Within the effective-mass approximation, the time-dependent Schrödinger equation is solved for a system with nonzero width of the ring and leads and finite potential-barrier heights, where we include smooth lead-ring connections. In the absence of a magnetic field, an analysis of the projection of the wave function over the different subband states shows that when the injected wave packet is within a single subband, the junction can scatter this wave packet into different subbands but remarkably at the second junction the wave packet is scattered back into the subband state of the incoming wave packet. If a magnetic field is applied perpendicularly to the ring plane, transmission and reflection probabilities exhibit Aharonov-Bohm (AB) oscillations and the outgoing electrons may end up in different subband states from those of the incoming electrons. Localized impurities, placed in the ring arms, influence the AB oscillation period and amplitude. For a single impurity or potential barrier of sufficiently strong strength, the period of the AB oscillations is halved while for two impurities localized in diametrically opposite points of the ring, the original AB period is recovered. A theoretical investigation of the confined states and time evolution of wave packets in T wires is also made, where a comparison between this system and the lead-ring junction is drawn. |
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Place of Publication |
Lancaster, Pa |
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Wos |
000270383300098 |
Publication Date |
2009-09-25 |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
40 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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Call Number |
UA @ lucian @ c:irua:79231 |
Serial |
3906 |
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Permanent link to this record |
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Author |
da Costa, D.R.; Chaves, A.; Farias, G.A.; Covaci, L.; Peeters, F.M. |
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Title |
Wave-packet scattering on graphene edges in the presence of a pseudomagnetic field |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
86 |
Issue |
11 |
Pages |
115434 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The scattering of a Gaussian wave packet in armchair and zigzag graphene edges is theoretically investigated by numerically solving the time-dependent Schrodinger equation for the tight-binding model Hamiltonian. Our theory allows us to investigate scattering in reciprocal space, and depending on the type of graphene edge we observe scattering within the same valley, or between different valleys. In the presence of an external magnetic field, the well-known skipping orbits are observed. However, our results demonstrate that in the case of a pseudomagnetic field, induced by nonuniform strain, the scattering by an armchair edge results in a nonpropagating edge state. |
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Wos |
000309174100005 |
Publication Date |
2012-09-21 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
28 |
Open Access |
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Notes |
; Discussions with E. B. Barros are gratefully acknowledged. This work was supported by the Brazilian Council for Research (CNPq), the Flemish Science Foundation (FWO-Vl), the ESF-EuroGRAPHENE (project CONGRAN), and the bilateral program between Flanders and Brazil. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:101833 |
Serial |
3907 |
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Permanent link to this record |
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Author |
Mayrock, O.; Wünsche, H.-J.; Henneberger, F.; Riva, C.; Schweigert, V.A.; Peeters, F.M. |
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Title |
Weakly localized biexcitons in quantum wells |
Type |
A1 Journal article |
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Year |
1999 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
60 |
Issue |
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Pages |
5582-5589 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Place of Publication |
Lancaster, Pa |
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Wos |
000082478600068 |
Publication Date |
2002-07-27 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0163-1829;1095-3795; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
17 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 1999 IF: NA |
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Call Number |
UA @ lucian @ c:irua:27009 |
Serial |
3912 |
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Permanent link to this record |
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Author |
Callewaert, V.; Saniz, R.; Barbiellini, B.; Bansil, A.; Partoens, B. |
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Title |
Application of the weighted-density approximation to the accurate description of electron-positron correlation effects in materials |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
96 |
Issue |
8 |
Pages |
085135 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We discuss positron-annihilation lifetimes for a set of illustrative bulk materials within the framework of the weighted-density approximation (WDA). The WDA can correctly describe electron-positron correlations in strongly inhomogeneous systems, such as surfaces, where the applicability of (semi-)local approximations is limited. We analyze the WDA in detail and show that the electrons which cannot screen external charges efficiently, such as the core electrons, cannot be treated accurately via the pair correlation of the homogeneous electron gas. We discuss how this problem can be addressed by reducing the screening in the homogeneous electron gas by adding terms depending on the gradient of the electron density. Further improvements are obtained when core electrons are treated within the LDA and the valence electron using the WDA. Finally, we discuss a semiempirical WDA-based approach in which a sum rule is imposed to reproduce the experimental lifetimes. |
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Wos |
000408342600003 |
Publication Date |
2017-08-24 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
6 |
Open Access |
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Notes |
Fonds Wetenschappelijk Onderzoek, G. 0224.14N ; U.S. Department of Energy, DE-FG02-07ER46352 DE-AC02-05CH11231 DE-SC0012575 ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
CMT @ cmt @c:irua:145703 |
Serial |
4703 |
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Permanent link to this record |
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Author |
Carvalho, J.C.N.; Ferreira, W.P.; Farias, G.A.; Peeters, F.M. |
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Title |
Yukawa particles confined in a channel and subject to a periodic potential : ground state and normal modes |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
83 |
Issue |
9 |
Pages |
094109-094109,12 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We consider a classical system of two-dimensional (2D) charged particles, interacting through a repulsive Yukawa potential exp(-r/λ)/r, and confined in a parabolic channel that limits the motion of the particles in the y direction. Along the x direction, the particles are subject to a periodic potential. The ground-state configurations and the normal-mode spectra of the system are obtained as a function of the periodicity and strength of the periodic potential (V0) and density. An interesting set of tunable ground-state configurations are found, with first- or second-order structural transitions between them. A configuration with particles aligned, perpendicular to the x direction, in each minimum of the periodic potential is obtained for V0 larger than some critical value that has a power-law dependence on the density. The phonon spectrum of different configurations was also calculated. A localization of the modes into a small frequency interval is observed for sufficiently large strength of the periodic potential, and a tunable gap in the phonon spectrum is found as a function of V0. |
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Wos |
000288119700001 |
Publication Date |
2011-03-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
9 |
Open Access |
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Notes |
; This work was supported by the Brazilian agencies CNPq and FUNCAP (PRONEX-Grant), and the bilateral projects between Flanders and Brazil and the Flemish Science Foundation (FWO-VI) and CNPq. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:88779 |
Serial |
3928 |
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Permanent link to this record |
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Author |
Adami, O.-A.; Jelić, Ž.L.; Xue, C.; Abdel-Hafiez, M.; Hackens, B.; Moshchalkov, V.V.; Milošević, M.V.; Van de Vondel, J.; Silhanek, A.V. |
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Title |
Onset, evolution, and magnetic braking of vortex lattice instabilities in nanostructured superconducting films |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review: B: condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
134506 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
In 1976, Larkin and Ovchinnikov [Zh. Eksp. Teor. Fiz. 68, 1915 (1975) [Sov. Phys.–JETP 41, 960 (1976)]] predicted that vortex matter in superconductors driven by an electrical current can undergo an abrupt dynamic transition from a flux-flow regime to a more dissipative state at sufficiently high vortex velocities. Typically, this transition manifests itself as a large voltage jump at a particular current density, so-called instability current density J∗, which is smaller than the depairing current. By tuning the effective pinning strength in Al films, using an artificial periodic pinning array of triangular holes, we show that a unique and well-defined instability current density exists if the pinning is strong, whereas a series of multiple voltage transitions appear in the relatively weaker pinning regime. This behavior is consistent with time-dependent Ginzburg-Landau simulations, where the multiple-step transition can be unambiguously attributed to the progressive development of vortex chains and subsequently phase-slip lines. In addition, we explore experimentally the magnetic braking effects, caused by a thick Cu layer deposited on top of the superconductor, on the instabilities and the vortex ratchet effect. |
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Wos |
000362433200003 |
Publication Date |
2015-10-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
21 |
Open Access |
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Notes |
ACKNOWLEDGMENTS: This work was partially supported by the Fonds de la Recherche Scientifique-FNRS, the Methusalem Funding of the Flemish Government, the Research Foundation-Flanders (FWO), and COST Action MP1201. The work of A.V.S. and Z.L.J. is partially supported by “Mandat d’Impulsion Scientifique” MIS F.4527.13 of the F.R.S.-FNRS. B.H. is an associate researcher of the Fonds de la Recherche Scientifique- FNRS. The authors thank J. Cuppens for the data analysis at the early stage of this work, R. Delamare for his valuable help during the fabrication of the samples, and G. Grimaldi for helpful discussions. |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
c:irua:128747 |
Serial |
3981 |
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Permanent link to this record |
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Author |
Aierken, Y.; Leenaerts, O.; Peeters, F.M. |
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Title |
Defect-induced faceted blue phosphorene nanotubes |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
104104 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The properties of a new class of phosphorene nanotubes (PNT) are investigated by performing first-principles calculations. We demonstrate that it is advantageous to use blue phosphorene in order to make small nanotubes and propose a way to create low-energy PNTs by the inclusion of defect lines. Five different types of defect lines are investigated and incorporated in various combinations. The resulting defect-induced faceted PNTs have negligible bending stresses which leads to a reduction in the formation energy with respect to round PNTs. Our armchair faceted PNTs have similar formation energies than the recently proposed multiphase faceted PNTs, but they have a larger variety of possible structures. Our zigzag faceted PNTs have lower formation energies than round tubes and multiphase faceted nanotubes. The electronic properties of the defect-induced faceted PNTs are determined by the defect lines which control the band gap and the shape of the electronic states at the band edges. These band gaps increase with the radius of the nanotubes and converge to those of isolated defect lines. |
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Language |
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Wos |
000361037200006 |
Publication Date |
2015-09-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
24 |
Open Access |
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Notes |
This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO-Vl). The computational resources and ser- vices used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Hercules Foundation and the Flemish Government, department EWI. |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
c:irua:127837 |
Serial |
4033 |
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Permanent link to this record |
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Author |
Aierken, Y.; Çakır, D.; Sevik, C.; Peeters, F.M. |
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Title |
Thermal properties of black and blue phosphorenes from a first-principles quasiharmonic approach |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
081408 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Different allotropes of phosphorene are possible of which black and blue phosphorus are the most stable. While blue phosphorus has isotropic properties, black phosphorus is strongly anisotropic in its electronic and optical properties due to its anisotropic crystal structure. In this work, we systematically investigated the lattice thermal properties of black and blue phosphorene by using first-principles calculations based on the quasiharmonic approximation approach. Similar to the optoelectronic and electronic properties, we predict that black phosphorene has highly anisotropic thermal properties, in contrast to the blue phase. The linear thermal expansion coefficients along the zigzag and armchair direction differ up to 20% in black phosphorene. The armchair direction of black phosphorene is more expandable as compared to the zigzag direction and the biaxial expansion of blue phosphorene under finite temperature. Our comparative analysis reveals that the inclusion of finite-temperature effects makes the blue phase thermodynamically more stable over the black phase above 135 K. |
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Place of Publication |
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Wos |
000359860700005 |
Publication Date |
2015-08-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
124 |
Open Access |
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Notes |
This work was supported by the Flemish Science Founda- tion (FWO-Vl) and the Methusalem foundation of the Flem- ish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Comput- ing Center (TR-Grid e-Infrastructure), and HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. C.S. acknowledges the support from Anadolu University (BAP-1407F335), and Turkish Academy of Sciences (TUBA-GEBIP). |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
c:irua:127754 |
Serial |
4034 |
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Permanent link to this record |
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Author |
da Costa, D.R.; Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
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Title |
Magnetic field dependence of energy levels in biased bilayer graphene quantum dots |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
93 |
Issue |
93 |
Pages |
085401 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using the tight-binding approach, we study the influence of a perpendicular magnetic field on the energy levels of hexagonal, triangular, and circular bilayer graphene (BLG) quantum dots (QDs) with zigzag and armchair edges. We obtain the energy levels for AB (Bernal)-stacked BLG QDs in both the absence and the presence of a perpendicular electric field (i.e., biased BLG QDs). We find different regions in the spectrum of biased QDs with respect to the crossing point between the lowest-electron and -hole Landau levels of a biased BLG sheet. Those different regions correspond to electron states that are localized at the center, edge, or corner of the BLG QD. Quantum Hall corner states are found to be absent in circular BLG QDs. The spatial symmetry of the carrier density distribution is related to the symmetry of the confinement potential, the position of zigzag edges, and the presence or absence of interlayer inversion symmetry. |
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Wos |
000369402400008 |
Publication Date |
2016-02-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
22 |
Open Access |
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Notes |
; This work was financially supported by CNPq, under Contract No. NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation under the Process No. BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the Bilateral programme between CNPq and FWO-Vl, and the Brazilian Program Science Without Borders (CsF). ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
c:irua:131623 |
Serial |
4038 |
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Permanent link to this record |
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Author |
Covaci, L.; Marsiglio, F. |
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Title |
Proximity effect and Josephson current in clean strong/weak/strong superconducting trilayers |
Type |
A1 Journal article |
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Year |
2006 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
73 |
Issue |
1 |
Pages |
014503 |
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Keywords |
A1 Journal article |
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Abstract |
Recent measurements of the Josephson critical current through LSCO/LCO/LSCO thin films showed an unusually large proximity effect. Using the Bogoliubov-de Gennes equations for a tight-binding Hamiltonian we describe the proximity effect in weak links between a superconductor with critical temperature T-c and one with critical temperature T-c('), where T-c > T-c('). The weak link (N-') is therefore a superconductor above its own critical temperature and the superconducting regions are considered to have either s-wave or d-wave symmetry. We note that the proximity effect is enhanced due to the presence of superconducting correlations in the weak link. The dc Josephson current is calculated, and we obtain a nonzero value for temperatures greater than T-c(') for sizes of the weak links that can be almost an order of magnitude greater than the conventional coherence length. Considering pockets of superconductivity in the N-' layer, we show that this can lead to an even larger effect on the Josephson critical current by effectively shortening the weak link. |
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Corporate Author |
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Place of Publication |
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Wos |
000235009000103 |
Publication Date |
2006-01-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121 |
ISBN |
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Additional Links |
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Impact Factor |
3.836 |
Times cited |
31 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2006 IF: 3.107 |
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Call Number |
UA @ lucian @ |
Serial |
4427 |
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Permanent link to this record |
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Author |
Dell'Anna, L.; Perali, A.; Covaci, L.; Neilson, D. |
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Title |
Using magnetic stripes to stabilize superfluidity in electron-hole double monolayer graphene |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
220502 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Experiments have confirmed that double monolayer graphene does not generate finite-temperature electron-hole superfluidity, because of very strong screening of the pairing attraction. The linear dispersing energy bands in monolayer graphene block any attempt to reduce the strength of the screening. We propose a hybrid device with two sheets of monolayer graphene in a modulated periodic perpendicular magnetic field. The field preserves the isotropic Dirac cones of the original monolayers but reduces the slope of the cones, making the monolayer Fermi velocity v(F) smaller. We demonstrate that with current experimental techniques, the reduction in vF can weaken the screening sufficiently to allow electron-hole superfluidity at measurable temperatures. |
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Place of Publication |
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Editor |
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Wos |
000366500100004 |
Publication Date |
2015-12-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
7 |
Open Access |
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Notes |
; We thank M. Zarenia for useful discussions. L.D. acknowledges financial support from MIUR: FIRB 2012, Grant No. RBFR12NLNA_002, and PRIN, Grant No. 2010LLKJBX. A.P. and D.N. acknowledge financial support from University of Camerino FAR project CESEMN. L.C. acknowledges financial support from Flemish Science Foundation (FWO). ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
c:irua:130211 |
Serial |
4069 |
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Permanent link to this record |
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Author |
Mulkers, J.; Milošević, M.V.; Van Waeyenberge, B. |
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Title |
Cycloidal versus skyrmionic states in mesoscopic chiral magnets |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
93 |
Issue |
93 |
Pages |
214405 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
When subjected to the interfacially induced Dzyaloshinskii-Moriya interaction, the ground state in thin ferromagnetic films with high perpendicular anisotropy is cycloidal. The period of this cycloidal state depends on the strength of the Dzyaloshinskii-Moriya interaction. In this work, we have studied the effect of confinement on the magnetic ground state and excited states, and we determined the phase diagram of thin strips and thin square platelets by means of micromagnetic calculations. We show that multiple cycloidal states with different periods can be stable in laterally confined films, where the period of the cycloids does not depend solely on the Dzyaloshinskii-Moriya interaction strength but also on the dimensions of the film. The more complex states comprising skyrmions are also found to be stable, though with higher energy. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000377298600006 |
Publication Date |
2016-06-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
28 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
c:irua:133919 |
Serial |
4081 |
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Permanent link to this record |
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Author |
Juchtmans, R.; Verbeeck, J. |
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Title |
Orbital angular momentum in electron diffraction and its use to determine chiral crystal symmetries |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review: B: condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
134108 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
In this work we present an alternative way to look at electron diffraction in a transmission electron microscope.
Instead of writing the scattering amplitude in Fourier space as a set of plane waves,we use the cylindrical Fourier transform to describe the scattering amplitude in a basis of orbital angular momentum (OAM) eigenstates. We show how working in this framework can be very convenient when investigating, e.g., rotation and screw-axis symmetries. For the latter we find selection rules on the OAM coefficients that unambiguously reveal the handedness of the screw axis. Detecting the OAM coefficients of the scattering amplitude thus offers the possibility to detect the handedness of crystals without the need for dynamical simulations, the thickness of the sample, nor the exact crystal structure. We propose an experimental setup to measure the OAM components where an image of the crystal is taken after inserting a spiral phase plate in the diffraction plane and perform multislice simulations on α quartz to demonstrate how the method indeed reveals the chirality. The experimental feasibility of the technique is discussed together with its main advantages with respect to chirality determination of screw axes. The method shows how the use of a spiral phase plate can be extended from a simple phase imaging technique to a tool to measure the local OAM decomposition of an electron wave, widening the field of interest well beyond chiral space group determination. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000362893100002 |
Publication Date |
2015-10-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
16 |
Open Access |
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Notes |
The authors acknowledge support from the FWO (As- pirant Fonds Wetenschappelijk Onderzoek–Vlaanderen), the EU under the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483-ESTEEM2, and ERC Starting Grant No. 278510 VORTEX; esteem2jra1; ECASJO; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
c:irua:129417 c:irua:129417UA @ admin @ c:irua:129417 |
Serial |
4089 |
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Permanent link to this record |
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Author |
Sobrino Fernandez, M.M.; Neek-Amal, M.; Peeters, F.M. |
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Title |
AA-stacked bilayer square ice between graphene layers |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
245428 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Water confined between two graphene layers with a separation of a few A forms a layered two-dimensional ice structure. Using large scale molecular dynamics simulations with the adoptable ReaxFF interatomic potential we found that flat monolayer ice with a rhombic-square structure nucleates between the graphene layers which is nonpolar and nonferroelectric. We provide different energetic considerations and H-bonding results that explain the interlayer and intralayer properties of two-dimensional ice. The controversial AA stacking found experimentally [Algara-Siller et al., Nature (London) 519, 443 (2015)] is consistent with our minimum-energy crystal structure of bilayer ice. Furthermore, we predict that an odd number of layers of ice has the same lattice structure as monolayer ice, while an even number of ice layers exhibits the square ice AA stacking of bilayer ice. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000366731800004 |
Publication Date |
2015-12-17 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
40 |
Open Access |
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Notes |
; This work was supported by the ESF-Eurographene project CONGRAN, and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
c:irua:130203 |
Serial |
4127 |
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Permanent link to this record |
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Author |
Chaves, A.; Low, T.; Avouris, P.; Çakir, D.; Peeters, F.M. |
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Title |
Anisotropic exciton Stark shift in black phosphorus |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
91 |
Issue |
91 |
Pages |
155311 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We calculate the excitonic spectrum of few-layer black phosphorus by direct diagonalization of the effective mass Hamiltonian in the presence of an applied in-plane electric field. The strong attractive interaction between electrons and holes in this system allows one to investigate the Stark effect up to very high ionizing fields, including also the excited states. Our results show that the band anisotropy in black phosphorus becomes evident in the direction-dependent field-induced polarizability of the exciton. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000353459200005 |
Publication Date |
2015-04-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
88 |
Open Access |
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Notes |
; Discussions with J. M. Pereira Jr. and J. S. de Souza are gratefully acknowledged. This work was supported by the Brazilian Council for Research (CNPq) through the PQ and Science Without Borders programs, the Flemish Science Foundation (FWO-Vl), the Methusalem programme of the Flemish government, and the Bilateral program (CNPq-FWO) between Flanders and Brazil. ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:132506 |
Serial |
4141 |
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Permanent link to this record |
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Author |
Bacaksiz, C.; Cahangirov, S.; Rubio, A.; Senger, R.T.; Peeters, F.M.; Sahin, H. |
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Title |
Bilayer SnS2 : tunable stacking sequence by charging and loading pressure |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
93 |
Issue |
93 |
Pages |
125403 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Employing density functional theory-based methods, we investigate monolayer and bilayer structures of hexagonal SnS2, which is a recently synthesized monolayer metal dichalcogenide. Comparison of the 1H and 1T phases of monolayer SnS2 confirms the ground state to be the 1T phase. In its bilayer structure we examine different stacking configurations of the two layers. It is found that the interlayer coupling in bilayer SnS2 is weaker than that of typical transition-metal dichalcogenides so that alternative stacking orders have similar structural parameters and they are separated with low energy barriers. A possible signature of the stacking order in the SnS2 bilayer has been sought in the calculated absorbance and reflectivity spectra. We also study the effects of the external electric field, charging, and loading pressure on the characteristic properties of bilayer SnS2. It is found that (i) the electric field increases the coupling between the layers at its preferred stacking order, so the barrier height increases, (ii) the bang gap value can be tuned by the external E field and under sufficient E field, the bilayer SnS2 can become a semimetal, (iii) the most favorable stacking order can be switched by charging, and (iv) a loading pressure exceeding 3 GPa changes the stacking order. The E-field tunable band gap and easily tunable stacking sequence of SnS2 layers make this 2D crystal structure a good candidate for field effect transistor and nanoscale lubricant applications. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000371405000005 |
Publication Date |
2016-03-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950;2469-9969; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
38 |
Open Access |
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Notes |
; The calculations were performed at TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). C.B., H.S., and R.T.S. acknowledge support from TUBITAK Project No. 114F397. H.S. is supported by an FWO Pegasus Marie Curie Fellowship. S.C. and A.R. acknowledge financial support from the Marie Curie grant FP7-PEOPLE-2013-IEF Project No. 628876, the European Research Council (ERC-2010-AdG-267374), and Spanish grant Grupos Consolidados (IT578-13). S.C. acknowledges support from the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No. 115F388. ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:132345 |
Serial |
4144 |
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Permanent link to this record |
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Author |
Galvan-Moya; Misko, V.R.; Peeters, F.M. |
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Title |
Chainlike transitions in Wigner crystals : sequential versus nonsequential |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
064112 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The structural transitions of the ground state of a system of repulsively interacting particles confined in a quasi-one-dimensional channel, and the effect of the interparticle interaction as well as the functional form of the confinement potential on those transitions are investigated. Although the nonsequential ordering of transitions (non-SOT), i.e., the 1 – 2 – 4 – 3 – 4 – 5 – 6 – ... sequence of chain configurations with increasing density, is widely robust as predicted in a number of theoretical studies, the sequential ordering of transitions (SOT), i.e., the 1 – 2 – 3 – 4 – 5 – 6 – ... chain, is found as the ground state for long-ranged interparticle interaction and hard-wall-like confinement potentials. We found an energy barrier between every two different phases around its transition point, which plays an important role in the preference of the system to follow either a SOT or a non-SOT. However, that preferential transition requires also the stability of the phases during the transition. Additionally, we analyze the effect of a small structural disorder on the transition between the two phases around its transition point. Our results show that a small deformation of the triangular structure changes dramatically the picture of the transition between two phases, removing in a considerable region the non-SOT in the system. This feature could explain the fact that the non-SOT is, up to now, not observed in experimental systems, and suggests a more advanced experimental setup to detect the non-SOT. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000359859400003 |
Publication Date |
2015-08-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
3 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Odysseus and Methusalem programmes of the Flemish government. Computational resources were provided by HPC infrastructure of the University of Antwerp (CalcUA) a division of the Flemish Supercomputer Center (VSC). ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:127753 |
Serial |
4148 |
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Permanent link to this record |
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Author |
Sadeghi, A.; Neek-Amal, M.; Berdiyorov, G.R.; Peeters, F.M. |
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Title |
Diffusion of fluorine on and between graphene layers |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
91 |
Issue |
91 |
Pages |
014304 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using first-principles calculations and reactive force field molecular dynamics simulations, we study the structural properties and dynamics of a fluorine (F) atom, either adsorbed on the surface of single layer graphene (F/GE) or between the layers of AB stacked bilayer graphene (F@ bilayer graphene). It is found that the diffusion of the F atom is very different in those cases, and that the mobility of the F atom increases by about an order of magnitude when inserted between two graphene layers. The obtained diffusion constant for F/GE is twice larger than that experimentally found for gold adatom and theoretically found for C-60 molecule on graphene. Our study provides important physical insights into the dynamics of fluorine atoms between and on graphene layers and explains the mechanism behind the separation of graphite layers due to intercalation of F atoms. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000349125800002 |
Publication Date |
2015-01-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
15 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI) and the Methusalem Foundation of the Flemish Government. ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:132561 |
Serial |
4161 |
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Permanent link to this record |
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Author |
Roy, P.; Torun, E.; de Groot, R.A. |
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Title |
Effect of doping and elastic properties in (Mn,Fe)2(Si,P) |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
93 |
Issue |
93 |
Pages |
094110 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Mixed magnetism (the coexistence of strong and weak magnetism in one material) is regarded as the origin of the giant magnetocaloric effect (GMCE). A good example is (Mn,Fe)(2)(Si,P), which is established as one of the best magnetocaloric materials available. Tuning the material properties are essential for optimizing its performance, and a straightforward way to do that is by doping. In this article, an ab initio electronic structure method was used to calculate the structure and magnetic properties of 3d-transition-metal-doped (Mn,Fe)(2)(Si,P) materials for magnetocaloric applications (transition metals are Cr, Co, Mn, Ni, Cu). For a steady performance, the material should be mechanically stable. A detailed analysis of the elastic constants shows that the mechanical stability of the (Mn,Fe)(2)(Si,P) system increases significantly by doping with boron without affecting the magnetic properties. Insights of the influence of doping enable future studies to understand and predict bettermagnetocaloric materials. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000372712100001 |
Publication Date |
2016-03-25 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950;2469-9969; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
9 |
Open Access |
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Notes |
; This work is part of an Industrial Partnership Programme (IPP I28) of Fundamenteel Onderzoek der Materie (FOM) (The Netherlands) and co-financed by BASF New Business. The authors would like to thank Phuong Thao Nguyen and Dr. Gilles A. de Wijs for very useful discussions. ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:133192 |
Serial |
4164 |
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Permanent link to this record |
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Author |
Bakalov, P.; Esfahani, D.N.; Covaci, L.; Peeters, F.M.; Tempere, J.; Locquet, J.-P. |
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Title |
Electric-field-driven Mott metal-insulator transition in correlated thin films : an inhomogeneous dynamical mean-field theory approach |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
93 |
Issue |
93 |
Pages |
165112 |
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Keywords |
A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT) |
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Abstract |
Simulations are carried out based on the dynamical mean-field theory (DMFT) in order to investigate the properties of correlated thin films for various values of the chemical potential, temperature, interaction strength, and applied transverse electric field. Application of a sufficiently strong field to a thin film at half filling leads to the appearance of conducting regions near the surfaces of the film, whereas in doped slabs the application of a field leads to a conductivity enhancement on one side of the film and a gradual transition to the insulating state on the opposite side. In addition to the inhomogeneous DMFT, a local density approximation (LDA) is considered in which the particle density n, quasiparticle residue Z, and spectral weight at the Fermi level A(ω=0) of each layer are approximated by a homogeneous bulk environment. A systematic comparison between the two approaches reveals that the less expensive LDA results are in good agreement with the DMFT approach, except close to the metal-to-insulator transition points and in the layers immediately at the film surfaces. LDA values for n are overall more reliable than those for Z and A(ω=0). The hysteretic behavior (memory effect) characteristic of the bulk doping driven Mott transition persists in the slab. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000373572700002 |
Publication Date |
2016-04-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
5 |
Open Access |
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Notes |
; This work was partially funded by the Flemish Fund for Scientific Research (FWO Belgium) under FWO Grant No. G.0520.10 and the joint FWF (Austria)-FWO Grant No. GOG6616N, and by the SITOGA FP7 project. Most of the calculations were performed on KU Leuven's ThinKing HPC cluster provided by the VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Government-department EWI. ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:132872 |
Serial |
4167 |
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Permanent link to this record |
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Author |
Pavlović, S.; Peeters, F.M. |
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Title |
Electronic properties of triangular and hexagonal MoS2 quantum dots |
Type |
A1 Journal article |
|
Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
91 |
Issue |
91 |
Pages |
155410 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using the tight-binding approach, we calculate the electronic structure of triangular and hexagonal MoS2 quantum dots. Due to the orbital asymmetry we show that it is possible to form quantum dots with the same shape but having different electronic properties. The electronic states of triangular and hexagonal quantum dots are explored, as well as the local and total density of states and the convergence towards the bulk spectrum with dot size is investigated. Our calculations show that: (1) edge states appear in the band gap, (2) that there are a larger number of electronic states in the conduction band as compared to the valence band, and (3) the relative number of edge states decreases with increasing dot size. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000352591200005 |
Publication Date |
2015-04-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
44 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI) and the Methusalem Foundation of the Flemish government. Stefan Pavlovic is supported by JoinEU-SEE IV, Erasmus Mundus Action 2 programme. We thank J. M. Pereira for interesting discussions. ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:132516 |
Serial |
4170 |
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Permanent link to this record |
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Author |
Craco, L.; Carara, S.S.; da Silva Pereira, T.A.; Milošević, M.V. |
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Title |
Electronic states in an atomistic carbon quantum dot patterned in graphene |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
93 |
Issue |
93 |
Pages |
155417 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We reveal the emergence of metallicKondo clouds in an atomistic carbon quantum dot, realized as a single-atom junction in a suitably patterned graphene nanoflake. Using density functional dynamical mean-field theory (DFDMFT) we show how correlation effects lead to striking features in the electronic structure of our device, and how those are enhanced by the electron-electron interactions when graphene is patterned at the atomistic scale. Our setup provides a well-controlled environment to understand the principles behind the orbital-selective Kondo physics and the interplay between orbital and spin degrees of freedom in carbon-based nanomaterials, which indicate new pathways for spintronics in atomically patterned graphene. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000373760900004 |
Publication Date |
2016-04-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950;2469-9969; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
6 |
Open Access |
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Notes |
; L.C.'s work is supported by CNPq (Proc. No. 307487/2014-8). Acknowledgment (L.C.) is also made to G. Seifert for discussions and the Department of Theoretical Chemistry at Technical University Dresden for hospitality. T.A.S.P. thanks PRONEX/CNPq/FAPEMAT 850109/2009 for financial support. M.V.M. acknowledges support from Research Foundation-Flanders (FWO), TOPBOF, and the CAPES-PVE program. ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:133260 |
Serial |
4171 |
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Permanent link to this record |
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Author |
da Costa, D.R.; Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
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Title |
Energy levels of bilayer graphene quantum dots |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
115437 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Within a tight binding approach we investigate the energy levels of hexagonal and triangular bilayer graphene (BLG) quantum dots (QDs) with zigzag and armchair edges. We study AA- and AB-(Bernal) stacked BLG QDs and obtain the energy levels in both the absence and the presence of a perpendicular electric field (i.e., biased BLG QDs). Our results show that the size dependence of the energy levels is different from that of monolayer graphene QDs. The energy spectrum of AB-stacked BLG QDs with zigzag edges exhibits edge states which spread out into the opened energy gap in the presence of a perpendicular electric field. We found that the behavior of these edges states is different for the hexagonal and triangular geometries. In the case of AA-stacked BLG QDs, the electron and hole energy levels cross each other in both cases of armchair and zigzag edges as the dot size or the applied bias increases. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000361663700003 |
Publication Date |
2015-09-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
21 |
Open Access |
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|
Notes |
; This work was financially supported by CNPq, under contract NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation under the process number BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the Bilateral programme between CNPq and FWO-Vl, and the Brazilian Program Science Without Borders (CsF). ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:128726 |
Serial |
4173 |
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Permanent link to this record |
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Author |
Mirzakhani, M.; Zarenia, M.; Ketabi, S.A.; da Costa, D.R.; Peeters, F.M. |
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Title |
Energy levels of hybrid monolayer-bilayer graphene quantum dots |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
93 |
Issue |
93 |
Pages |
165410 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Often real samples of graphene consist of islands of both monolayer and bilayer graphene. Bound states in such hybrid quantum dots are investigated for (i) a circular single-layer graphene quantum dot surrounded by an infinite bilayer graphene sheet and (ii) a circular bilayer graphene quantum dot surrounded by an infinite single-layer graphene. Using the continuum model and applying zigzag boundary conditions at the single-layer-bilayer graphene interface, we obtain analytical results for the energy levels and the corresponding wave spinors. Their dependence on perpendicular magnetic and electric fields are studied for both types of quantum dots. The energy levels exhibit characteristics of interface states, and we find anticrossings and closing of the energy gap in the presence of a bias potential. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000373572700004 |
Publication Date |
2016-04-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950;2469-9969; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
26 |
Open Access |
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Notes |
; This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO)-CNPq project between Flanders and Brazil and the Brazilian Science Without Borders program. ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:133261 |
Serial |
4174 |
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Permanent link to this record |
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Author |
Peymanirad, F.; Neek Amal, M.; Beheshtian, J.; Peeters, F.M. |
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Title |
Graphene-silicene bilayer : a nanocapacitor with permanent dipole and piezoelectricity effect |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
155113 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using density functional theory, we study the electronic properties of a graphene-silicene bilayer (GSB). A single layer of silicene binds to the graphene layer with adhesion energy of about 25 meV/atom. This adhesion energy between the two layers follows accurately the well-known -1/z(2) dispersion energy as found between two infinite parallel plates. In small flakes of GSB with hydrogenated edges, negative charge is transferred from the graphene layer to the silicene layer, producing a permanent and a switchable polar bilayer, while in an infinite GSB, the negative charge is transferred from the silicene layer to the graphene layer. The graphene-silicene bilayer is a good candidate for a nanocapacitor with piezoelectric capabilities. We found that the permanent dipole of the bilayer can be tuned by an external perpendicular electric field. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000362493400002 |
Publication Date |
2015-10-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
17 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:128762 |
Serial |
4188 |
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Permanent link to this record |
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Author |
Kang, J.; Horzum, S.; Peeters, F.M. |
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Title |
Heterostructures of graphene and nitrogenated holey graphene: Moire pattern and Dirac ring |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
195419 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Nitrogenated holey graphene (NHG) is a recently synthesized two-dimensional material. In this paper the structural and electronic properties of heterostructures of graphene and NHG are investigated using first-principles and tight-binding calculations. Due to the lattice mismatch between NHG and graphene, the formation of a moire pattern is preferred in the graphene/NHG heterostructure, instead of a lattice-coherent structure. In moire-patterned graphene/NHG, the band gap opening at the K point is negligible, and the linear band dispersion of graphene survives. Applying an electric field modifies the coupling strength between the two atomic layers. The Fermi velocity upsilon(F) is reduced as compared to the one of pristine graphene, and its magnitude depends on the twist angle theta between graphene and NHG: For theta = 0 degrees, upsilon(F) is 30% of that of graphene, and it increases rapidly to a value of 80% with increasing theta. The heterostructure exhibits electron-hole asymmetry in upsilon(F), which is large for small theta. In NHG encapsulated between two graphene layers, a “Dirac ring” appears around the K point. Its presence is robust with respect to the relative stacking of the two graphene layers. These findings can be useful for future applications of graphene/NHG heterostructures. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000364998000006 |
Publication Date |
2015-11-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
33 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:130266 |
Serial |
4189 |
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Permanent link to this record |
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Author |
da Costa; Zarenia, M.; Chaves, A.; Pereira, J.M., Jr.; Farias, G.A.; Peeters, F.M. |
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Title |
Hexagonal-shaped monolayer-bilayer quantum disks in graphene : a tight-binding approach |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
94 |
Issue |
94 |
Pages |
035415 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using the tight-binding approach, we investigate confined states in two different hybrid monolayer-bilayer systems: (i) a hexagonal monolayer area surrounded by bilayer graphene in the presence of a perpendicularly applied electric field and (ii) a hexagonal bilayer graphene dot surrounded by monolayer graphene. The dependence of the energy levels on dot size and external magnetic field is calculated. We find that the energy spectrum for quantum dots with zigzag edges consists of states inside the gap which range from dot-localized states, edge states, to mixed states coexisting together, whereas for dots with armchair edges, only dot-localized states are observed. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000379502200008 |
Publication Date |
2016-07-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950;2469-9969; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
3.836 |
Times cited |
11 |
Open Access |
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|
Notes |
; This work was financially supported by CNPq, under contract NanoBioEstruturas No. 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation, under the process No. BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the Bilateral programme between CNPq and FWO-Vl, the Brazilian Program Science Without Borders (CsF), and the Lemann Foundation. ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:134947 |
Serial |
4190 |
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Permanent link to this record |
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Author |
Zha, G.-Q.; Covaci, L.; Peeters, F.M.; Zhou, S.-P. |
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Title |
Majorana zero-energy modes and spin current evolution in mesoscopic superconducting loop systems with spin-orbit interaction |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
094516 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The Majorana zero modes and persistent spin current in mesoscopic d-wave-superconducting loops with spin-orbit (SO) interaction are investigated by numerically solving the spin-generalized Bogoliubov-de Gennes equations self-consistently. For some appropriate strength of the SO coupling, Majorana zero-energy states and sharp jumps of the spin-polarized currents can be observed when the highest energy levels cross the Fermi energy in the spectrum, leading to spin currents with opposite chirality flowing near the inner and outer edges of the sample. When the threaded magnetic flux turns on, four flux-dependent patterns of the persistent spin current with step-like features show up, accompanied by Majorana edge modes at flux values where the energy gap closes. Moreover, the Majorana zero mode is highly influenced by the direction of the Zeeman field. A finite in-plane field can lead to the gap opening since the inversion symmetry is broken. Remarkably, multiple Majorana zero-energy states occur in the presence of an out-of-plane field h(z), and the number of steps in the spin current evolution can be effectively tuned by the field strength due to the shift of Majorana zero modes. Finally, when the loop sample contains surface indentation defects, zero-energy modes can always show up in the presence of an appropriate h(z). Interestingly, multiple Majorana states may be present in the system with a corner defect even if h(z) = 0. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000362081000002 |
Publication Date |
2015-09-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
3.836 |
Times cited |
11 |
Open Access |
|
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|
Notes |
; This work was supported by National Natural Science Foundation of China under Grants No. 61371020, No. 61271163, and No. 61571277, by the Visiting Scholar Program of Shanghai Municipal Education Commission, and by the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:132467 |
Serial |
4203 |
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Permanent link to this record |
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Author |
Ghorbanfekr-Kalashami, H.; Neek-Amal, M.; Peeters, F.M. |
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Title |
N-doped graphene : polarization effects and structural properties |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
93 |
Issue |
93 |
Pages |
174112 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The structural and mechanical properties of N-doped graphene (NG) are investigated using reactive force field (ReaxFF) potentials in large-scale molecular dynamics simulations. We found that ripples, which are induced by the dopants, change the roughness of NG, which depends on the number of dopants and their local arrangement. For any doping ratio N/C, the NG becomes ferroelectric with a net dipole moment. The formation energy increases nonlinearly with N/C ratio, while the Young's modulus, tensile strength, and intrinsic strain decrease with the number of dopants. Our results for the structural deformation and the thermoelectricity of the NG sheet are in good agreement with recent experiments and ab initio calculations. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000376245900002 |
Publication Date |
2016-05-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950;2469-9969; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
3.836 |
Times cited |
15 |
Open Access |
|
|
|
Notes |
; This work was supported by the ESF-Eurographene project CONGRAN, and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:134148 |
Serial |
4212 |
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Permanent link to this record |