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	Author	Chaves, A.; Neilson, D.
	Title	Exotic state seen at high temperatures			Type	Editorial
	Year	2019	Publication	Nature	Abbreviated Journal	Nature
	Volume	574	Issue	7776	Pages	39-40
	Keywords	Editorial; Engineering sciences. Technology; Condensed Matter Theory (CMT)
	Abstract	The phenomenon of Bose-Einstein condensation is typically limited to extremely low temperatures. The effect has now been spotted at much higher temperatures for particles called excitons in atomically thin semiconductors.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000488832500022	Publication Date	2019-10-02
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0028-0836	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	40.137	Times cited	2	Open Access
	Notes	; ;			Approved	Most recent IF: 40.137
	Call Number	UA @ admin @ c:irua:163739			Serial	5413
Permanent link to this record



	Author	Kahraman, Z.; Baskurt, M.; Yagmurcukardes, M.; Chaves, A.; Sahin, H.
	Title	Stable Janus TaSe₂ single-layers via surface functionalization			Type	A1 Journal article
	Year	2021	Publication	Applied Surface Science	Abbreviated Journal	Appl Surf Sci
	Volume	538	Issue		Pages	148064
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	First-principles calculations are performed in order to investigate the formation of Janus structures of single layer TaSe2. The structural optimizations and phonon band dispersions reveal that the formation and stability of hydrogenated (HTaSe2), fluorinated (FTaSe2), and the one-side hydrogenated and one-side fluorinated (Janus-HTaSe2F) single-layers are feasible in terms of their phonon band dispersions. It is shown that bare metallic single-layer TaSe2 can be turned into a semiconductor as only one of its surface is functionalized while it remains as a metal via its two surfaces functionalization. In addition, the semiconducting nature of single-layers HTaSe2 and FTaSe2 and the metallic behavior of Janus TaSe2 are found to be robust under applied uniaxal strains. Further analysis on piezoelectric properties of the predicted single-layers reveal the enhanced in-plane and out of-plane piezoelectricity via formed Janus-HTaSe2F. Our study indicates that single-layer TaSe2 is a suitable host material for surface functionalization via fluorination and hydrogenation which exhibit distinctive electronic and vibrational properties.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000595860900001	Publication Date	2020-10-16
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0169-4332	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.387	Times cited		Open Access	Not_Open_Access
	Notes	; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid eInfrastructure). HS acknowledges support from Turkiye Bilimler Akademisi -Turkish Academy of Sciences under the GEBIP program. This work was supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ;			Approved	Most recent IF: 3.387
	Call Number	UA @ admin @ c:irua:174964			Serial	6699
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	Author	Chaves, A.; Peeters, F.M.
	Title	Tunable effective masses of magneto-excitons in two-dimensional materials			Type	A1 Journal article
	Year	2021	Publication	Solid State Communications	Abbreviated Journal	Solid State Commun
	Volume	334	Issue		Pages	114371
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Excitonic properties of Ge2H2 and Sn2H2, also known as Xanes, are investigated within the effective mass model. A perpendicularly applied magnetic field induces a negative shift on the exciton center-of-mass kinetic energy that is approximately quadratic with its momentum, thus pushing down the exciton dispersion curve and flattening it. This can be interpreted as an increase in the effective mass of the magneto-exciton, tunable by the field intensity. Our results show that in low effective mass two-dimensional semiconductors, such as Xanes, the applied magnetic field allows one to tune the magneto-exciton effective mass over a wide range of values.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000670329600003	Publication Date	2021-05-14
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0038-1098	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor	1.554	Times cited		Open Access	Not_Open_Access
	Notes				Approved	Most recent IF: 1.554
	Call Number	UA @ admin @ c:irua:179762			Serial	7037
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	Author	Dantas, D.S.; Chaves, A.; Farias, G.A.; Ramos, A.C.A.; Peeters, F.M.
	Title	Low-dimensional confining structures on the surface of helium films suspended on designed cavities			Type	A1 Journal article
	Year	2013	Publication	Journal of low temperature physics	Abbreviated Journal	J Low Temp Phys
	Volume	173	Issue	3-4	Pages	207-226
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We investigate the formation of quantum confined structures on the surface of a liquid helium film suspended on a nanostructured substrate. We show theoretically that, by nanostructuring the substrate, it is possible to change the geometry of the liquid helium surface, opening the possibility of designing and controlling the formation of valleys with different shapes. By applying an external electric field perpendicular to the substrate plane, surface electrons can be trapped into these valleys, as in a quantum dot. We investigate how the external parameters, such as the electric field strength and the height of the liquid helium bath, can be tuned to control the energy spectrum of the trapped surface electrons.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	New York	Editor
	Language		Wos	000324820300008	Publication Date	2013-08-22
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0022-2291;1573-7357;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	1.3	Times cited	1	Open Access
	Notes	; This work has received financial support from the Brazilian National Research Council (CNPq), Fundacao Cearense de Apoio ao Desenvolvimento Cientifico e Tecnologico (Funcap), CAPES and Pronex/CNPq/Funcap. This work was partially supported by the Flemish Science Foundation (FWO-Vl) and the bilateral project between CNPq and FWO-Vl. ;			Approved	Most recent IF: 1.3; 2013 IF: 1.036
	Call Number	UA @ lucian @ c:irua:111140			Serial	1845
Permanent link to this record



	Author	Andelkovic, M.; Rakhimov, K.Y.; Chaves, A.; Berdiyorov, G.R.; Milošević, M.V.
	Title	Wave-packet propagation in a graphene geometric diode			Type	A1 Journal article
	Year	2023	Publication	Physica. E: Low-dimensional systems and nanostructures	Abbreviated Journal
	Volume	147	Issue		Pages	115607-4
	Keywords	A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
	Abstract	Dynamics of electron wave-packets is studied using the continuum Dirac model in a graphene geometric diode where the propagation of the wave packet is favored in certain direction due to the presence of geometric constraints. Clear rectification is obtained in the THz frequency range with the maximum rectification level of 3.25, which is in good agreement with recent experiments on graphene ballistic diodes. The rectification levels are considerably higher for systems with narrower channels. In this case, the wave packet transmission probabilities and rectification rate also strongly depend on the energy of the incident wave packet, as a result of the quantum nature of energy levels along such channels. These findings can be useful for fundamental understanding of the charge carrier dynamics in graphene geometry diodes.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000903737000003	Publication Date	2022-12-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1386-9477	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.3	Times cited	1	Open Access	OpenAccess
	Notes				Approved	Most recent IF: 3.3; 2023 IF: 2.221
	Call Number	UA @ admin @ c:irua:193497			Serial	7351
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	Author	Blundo, E.; Faria, P.E., Jr.; Surrente, A.; Pettinari, G.; Prosnikov, M.A.; Olkowska-Pucko, K.; Zollner, K.; Wozniak, T.; Chaves, A.; Kazimierczuk, T.; Felici, M.; Babinski, A.; Molas, M.R.; Christianen, P.C.M.; Fabian, J.; Polimeni, A.
	Title	Strain-Induced Exciton Hybridization in WS2 Monolayers Unveiled by Zeeman-Splitting Measurements			Type	A1 Journal article
	Year	2022	Publication	Physical review letters	Abbreviated Journal
	Volume	129	Issue	6	Pages	067402
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Mechanical deformations and ensuing strain are routinely exploited to tune the band gap energy and to enhance the functionalities of two-dimensional crystals. In this Letter, we show that strain leads also to a strong modification of the exciton magnetic moment in WS2 monolayers. Zeeman-splitting measurements under magnetic fields up to 28.5 T were performed on single, one-layer-thick WS2 microbubbles. The strain of the bubbles causes a hybridization of k-space direct and indirect excitons resulting in a sizable decrease in the modulus of they factor of the ground-state exciton. These findings indicate that strain may have major effects on the way the valley number of excitons can be used to process binary information in two-dimensional crystals.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000842367600007	Publication Date	2022-08-04
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0031-9007; 1079-7114	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor		Times cited		Open Access	OpenAccess
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:198538			Serial	8936
Permanent link to this record



	Author	Chaves, A.; Moura, V.N.; Linard, F.J.A.; Covaci, L.; Milošević, M.V.
	Title	Tunable magnetic focusing using Andreev scattering in superconductor-graphene hybrid devices			Type	A1 Journal article
	Year	2020	Publication	Journal Of Applied Physics	Abbreviated Journal	J Appl Phys
	Volume	128	Issue	12	Pages	124303
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
	Abstract	We perform the wavepacket dynamics simulation of a graphene-based device where propagating electron trajectories are tamed by an applied magnetic field toward a normal/superconductor interface. The magnetic field controls the incidence angle of the incoming electronic wavepacket at the interface, which results in the tunable electron-hole ratio in the reflected wave function due to the angular dependence of the Andreev reflection. Here, mapped control of the quasiparticle trajectories by the external magnetic field not only defines an experimental probe for fundamental studies of the Andreev reflection in graphene but also lays the foundation for further development of magnetic focusing devices based on nanoengineered superconducting two-dimensional materials.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000576393200002	Publication Date	2020-09-28
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-8979; 1089-7550	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.2	Times cited	1	Open Access	Not_Open_Access
	Notes	; This work was supported by the Brazilian Council for Research (CNPq) through the PRONEX/FUNCAP and PQ programs and by the Research Foundation-Flanders (FWO). ;			Approved	Most recent IF: 3.2; 2020 IF: 2.068
	Call Number	UA @ admin @ c:irua:172730			Serial	6639
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	Author	Lavor, I.R.; da Costa, D.R.; Covaci, L.; Milošević, M.V.; Peeters, F.M.; Chaves, A.
	Title	Zitterbewegung of moiré excitons in twisted MoS₂/WSe₂ heterobilayers			Type	A1 Journal article
	Year	2021	Publication	Physical review letters	Abbreviated Journal
	Volume	127	Issue	10	Pages	106801
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
	Abstract	The moire pattern observed in stacked noncommensurate crystal lattices, such as heterobilayers of transition metal dichalcogenides, produces a periodic modulation of their band gap. Excitons subjected to this potential landscape exhibit a band structure that gives rise to a quasiparticle dubbed the moire exciton. In the case of MoS2/WSe2 heterobilayers, the moire trapping potential has honeycomb symmetry and, consequently, the moire exciton band structure is the same as that of a Dirac-Weyl fermion, whose mass can be further tuned down to zero with a perpendicularly applied field. Here we show that, analogously to other Dirac-like particles, the moire exciton exhibits a trembling motion, also known as Zitterbewegung, whose long timescales are compatible with current experimental techniques for exciton dynamics. This promotes the study of the dynamics of moire excitons in van der Waals heterostructures as an advantageous solid-state platform to probe Zitterbewegung, broadly tunable by gating and interlayer twist angle.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000692200800020	Publication Date	2021-08-31
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1079-7114	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor		Times cited	4	Open Access	OpenAccess
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:181599			Serial	6896
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	Author	Gjerding, M.N.; Cavalcante, L.S.R.; Chaves, A.; Thygesen, K.S.
	Title	Efficient Ab initio modeling of dielectric screening in 2D van der Waals materials : including phonons, substrates, and doping			Type	A1 Journal article
	Year	2020	Publication	Journal Of Physical Chemistry C	Abbreviated Journal	J Phys Chem C
	Volume	124	Issue	21	Pages	11609-11616
	Keywords	A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
	Abstract	The quantum electrostatic heterostructure (QEH) model allows for efficient computation of the dielectric screening properties of layered van der Waals (vdW)-bonded heterostructures in terms of the dielectric functions of the individual two-dimensional (2D) layers. Here, we extend the QEH model by including (1) contributions to the dielectric function from infrared active phonons in the 2D layers, (2) screening from homogeneous bulk substrates, and (3) intraband screening from free carriers in doped 2D semiconductor layers. We demonstrate the potential of the extended QEH model by calculating the dispersion of coupled phonons in multilayer stacks of hexagonal boron-nitride (hBN), the strong hybridization of plasmons and optical phonons in graphene/hBN heterostructures, the effect of substrate screening on the exciton series of monolayer MoS2, and the properties of hyperbolic plasmons in a doped phosphorene sheet. The new QEH code is distributed as a Python package with a simple command line interface and a comprehensive library of dielectric building blocks for the most common 2D materials, providing an efficient open platform for dielectric modeling of realistic vdW heterostructures.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000614615900022	Publication Date	2020-05-04
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1932-7447; 1932-7455	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.7	Times cited		Open Access
	Notes				Approved	Most recent IF: 3.7; 2020 IF: 4.536
	Call Number	UA @ admin @ c:irua:176187			Serial	7852
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	Author	Frota, D.A.; Chaves, A.; Ferreira, W.P.; Farias, G.A.; Milošević, M.V.
	Title	Superconductor-ferromagnet bilayer under external drive : the role of vortex-antivortex matter			Type	A1 Journal article
	Year	2016	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	119	Issue	119	Pages	093912
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Using advanced Ginzburg-Landau simulations, we study the superconducting state of a thin superconducting film under a ferromagnetic layer, separated by an insulating oxide, in applied external magnetic field and electric current. The taken uniaxial ferromagnet is organized into a series of parallel domains with alternating polarization of out-of-plane magnetization, sufficiently strong to induce vortex-antivortex pairs in the underlying superconductor in absence of other magnetic field. We show the organization of such vortex-antivortex matter into rich configurations, some of which are not matching the periodicity of the ferromagnetic film. The variety of possible configurations is enhanced by applied homogeneous magnetic field, where additional vortices in the superconductor may lower the energy of the system by either annihilating the present antivortices under negative ferromagnetic domains or by lowering their own energy after positioning under positive ferromagnetic domains. As a consequence, both the vortex-antivortex reordering in increasing external field and the evolution of the energy of the system are highly nontrivial. Finally, we reveal the very interesting effects of applied dc electric current on the vortex-antivortex configurations, since resulting Lorentzian force has opposite direction for vortices and antivortices, while direction of the applied current with respect to ferromagnetic domains is of crucial importance for the interaction of the applied and the Meissner current, as well as the consequent vortex-antivortex dynamics-both of which are reflected in the anisotropic critical current of the system. (C) 2016 AIP Publishing LLC.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000372351900018	Publication Date	2016-03-07
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-8979; 1089-7550	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.068	Times cited	4	Open Access
	Notes	; This work was supported by the Brazilian agencies CNPq, PRONEX/FUNCAP, and CAPES, and the Research Foundation-Flanders (FWO). ;			Approved	Most recent IF: 2.068
	Call Number	UA @ lucian @ c:irua:133200			Serial	4255
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	Author	de Sousa, A.A.; Chaves, A.; Pereira, T.A.S.; Farias, G.A.; Peeters, F.M.
	Title	Quantum tunneling between bent semiconductor nanowires			Type	A1 Journal article
	Year	2015	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	118	Issue	118	Pages	174301
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We theoretically investigate the electronic transport properties of two closely spaced L-shaped semiconductor quantum wires, for different configurations of the output channel widths as well as the distance between the wires. Within the effective-mass approximation, we solve the time-dependent Schrodinger equation using the split-operator technique that allows us to calculate the transmission probability, the total probability current, the conductance, and the wave function scattering between the energy subbands. We determine the maximum distance between the quantum wires below which a relevant non-zero transmission is still found. The transmission probability and the conductance show a strong dependence on the width of the output channel for small distances between the wires. (C) 2015 AIP Publishing LLC.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000364584200020	Publication Date	2015-11-02
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-8979; 1089-7550	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.068	Times cited	7	Open Access
	Notes	; A. A. Sousa was financially supported by CAPES, under the PDSE Contract No. BEX 7177/13-5. T. A. S. Pereira was financially supported by PRONEX/CNPq/FAPEMAT 850109/2009 and by CAPES under process BEX 3299/13-9. This work was financially supported by PRONEX/CNPq/FUNCAP, the Science Without Borders program and the bilateral project CNPq-FWO. ;			Approved	Most recent IF: 2.068; 2015 IF: 2.183
	Call Number	UA @ lucian @ c:irua:129544			Serial	4234
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	Author	de Sousa, A.A.; Chaves, A.; Pereira, T.A.S.; de Farias, G.A.; Peeters, F.M.
	Title	Wave packet propagation through branched quantum rings under applied magnetic fields			Type	A1 Journal article
	Year	2019	Publication	Physica. E: Low-dimensional systems and nanostructures	Abbreviated Journal	Physica E
	Volume	114	Issue	114	Pages	113598
	Keywords	A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
	Abstract	We investigate the effect of opening and closing pathways on the dynamics of electron wave packets in semiconductor quantum rings with different geometries. Our analysis is based on the time evolution of an electron wave packet, within the effective-mass approximation. We demonstrate that opening an extra channel in the quantum ring does not necessarily improve the electron transmission and, depending on the extra channel width, may even reduce it, either due to enhancement of quantum scattering or due to interference. In the latter case, transmission reduction can be controlled through the Aharonov-Bohm phase of the wave function, via an applied magnetic field. It is also shown that, closing one of the channels of the quantum ring, system improves the transmission probability under specific conditions, an effect which is a quantum analog of the Braess paradox.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000482637000039	Publication Date	2019-06-13
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1386-9477	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.221	Times cited		Open Access
	Notes	; This work was financially supported by PRONEX/CNPq/FUNCAP, Science Without Boards (Ciencias Sem Fronteiras) and the bilateral project CNPq-FWO. A. A. Sousa was financially supported by CAPES, under the PDSE contract BEX 7177/ 13-5. T. A. S. Pereira was financially supported by PRONEX/CNPq/FAPEMAT 850109/ 2009 and by CAPES under process BEX 3299/13-9. ;			Approved	Most recent IF: 2.221
	Call Number	UA @ admin @ c:irua:162777			Serial	5432
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	Author	Santos-Castro, G.; Pandey, T.; Bruno, C.H.V.; Santos Caetano, E.W.; Milošević, M.V.; Chaves, A.; Freire, V.N.
	Title	Silicon and germanium adamantane and diamantane monolayers as two-dimensional anisotropic direct-gap semiconductors			Type	A1 Journal article
	Year	2023	Publication	Physical review B	Abbreviated Journal
	Volume	108	Issue	3	Pages	035302-35310
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Structural and electronic properties of silicon and germanium monolayers with two different diamondoid crystal structures are detailed ab initio. Our results show that, despite Si and Ge being well-known indirect gap semiconductors in their bulk form, their adamantane and diamantane monolayers can exhibit optically active direct gap in the visible frequency range, with highly anisotropic effective masses, depending on the monolayer crystal structure. Moreover, we reveal that gaps in these materials are highly tunable with applied strain. These stable monolayer forms of Si and Ge are therefore expected to help bridging the gap between the fast growing area of opto-electronics in two-dimensional materials and the established silicon-based technologies.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001074455300012	Publication Date	2023-07-05
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:200348			Serial	9089
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	Author	Lima, I.L.C.; Milošević, M.V.; Peeters, F.M.; Chaves, A.
	Title	Tuning of exciton type by environmental screening			Type	A1 Journal article
	Year	2023	Publication	Physical review B	Abbreviated Journal
	Volume	108	Issue	11	Pages	115303-115308
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We theoretically investigate the binding energy and electron-hole (e-h) overlap of excitonic states confined at the interface between two-dimensional materials with type-II band alignment, i.e., with lowest conduction and highest valence band edges placed in different materials, arranged in a side-by-side planar heterostructure. We propose a variational procedure within the effective mass approximation to calculate the exciton ground state and apply our model to a monolayer MoS2/WS2 heterostructure. The role of nonabrupt interfaces between the materials is accounted for in our model by assuming a WxMo1-xS2 alloy around the interfacial region. Our results demonstrate that (i) interface-bound excitons are energetically favorable only for small interface thickness and/or for systems under high dielectric screening by the materials surrounding the monolayer, and that (ii) the interface exciton binding energy and its e-h overlap are controllable by the interface width and dielectric environment.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001077758300002	Publication Date	2023-09-08
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:200356			Serial	9110
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	Author	Linard, F.J.A.; Moura, V.N.; Covaci, L.; Milošević, M.V.; Chaves, A.
	Title	Wave-packet scattering at a normal-superconductor interface in two-dimensional materials : a generalized theoretical approach			Type	A1 Journal article
	Year	2023	Publication	Physical review B	Abbreviated Journal
	Volume	107	Issue	16	Pages	165306-165309
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
	Abstract	A wave-packet time evolution method, based on the split-operator technique, is developed to investigate the scattering of quasiparticles at a normal-superconductor interface of arbitrary profile and shape. As a practical application, we consider a system where low-energy electrons can be described as Dirac particles, which is the case for most two-dimensional materials, such as graphene and transition-metal dichalcogenides. However, the method is easily adapted for other cases such as electrons in few-layer black phosphorus or any Schrodinger quasiparticles within the effective mass approximation in semiconductors. We employ the method to revisit Andreev reflection in mono-, bi-, and trilayer graphene, where specular-and retro-reflection cases are observed for electrons scattered by a steplike superconducting region. The effect of opening a zero-gap channel across the superconducting region on the electron and hole scattering is also addressed, as an example of the versatility of the technique proposed here.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000974675700006	Publication Date	2023-04-14
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.7	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 3.7; 2023 IF: 3.836
	Call Number	UA @ admin @ c:irua:196709			Serial	8954
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	Author	Moura, V.N.; Dantas, D.S.; Farias, G.A.; Chaves, A.; Milošević, M.V.
	Title	Latent superconductivity at parallel interfaces in a superlattice dominated by another collective quantum phase			Type	A1 Journal article
	Year	2022	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	106	Issue	1	Pages	014516-10
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We theoretically examine behavior of superconductivity at parallel interfaces separating the domains of another dominant collective excitation, such as charge density waves or spin density waves. Due to their competitive coupling in a two-component Ginzburg-Landau model, suppression of the dominant order parameter at the interfacial planes allows for nucleation of the (hidden) superconducting order parameter at those planes. In such a case, we demonstrate how the number of the parallel interfacial planes and the distance between them are linked to the number and the size of the emerging superconducting gaps in the system, as well as the versatility and temperature evolution of the possible superconducting phases. These findings bear relevance to a broad selection of known layered superconducting materials, as well as to further design of artificial (e.g., oxide) superlattices, where the interplay between competing order parameters paves the way towards otherwise unattainable superconducting states, some with enhanced superconducting critical temperature.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000834346000004	Publication Date	2022-07-22
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor	3.7	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 3.7
	Call Number	UA @ admin @ c:irua:189520			Serial	7179
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	Author	Chaves, A.; Sousa, G.O.; Khaliji, K.; da Costa, D.R.; Farias, G.A.; Low, T.
	Title	Signatures of subband excitons in few-layer black phosphorus			Type	A1 Journal article
	Year	2021	Publication	Physical Review B	Abbreviated Journal	Phys Rev B
	Volume	103	Issue	16	Pages	165428
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Recent experimental measurements of light absorption in few-layer black phosphorus (BP) revealed a series of high and sharp peaks, interspersed by pairs of lower and broader features. Here, we propose a theoretical model for these excitonic states in few-layer BP within a continuum approach for the in-plane degrees of freedom and a tight-binding approximation that accounts for interlayer couplings. This yields excitonic transitions between different combinations of the subbands created by the coupled BP layers, which leads to a series of high and low oscillator strength excitonic states, consistent with the experimentally observed bright and dark exciton peaks, respectively. The main characteristics of such subband exciton states, as well as the possibility to control their energies and oscillator strengths via applied electric and magnetic fields, are discussed, towards a full understanding of the excitonic spectrum of few-layer BP and its tunability.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000647175200002	Publication Date	2021-04-28
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 3.836
	Call Number	UA @ admin @ c:irua:178384			Serial	8523
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	Author	Wozniak, T.; Faria, P.E., Jr.; Seifert, G.; Chaves, A.; Kunstmann, J.
	Title	Exciton g factors of van der Waals heterostructures from first-principles calculations			Type	A1 Journal article
	Year	2020	Publication	Physical Review B	Abbreviated Journal	Phys Rev B
	Volume	101	Issue	23	Pages	235408-235411
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	External fields are a powerful tool to probe optical excitations in a material. The linear energy shift of an excitation in a magnetic field is quantified by its effective g factor. Here we show how exciton g factors and their sign can be determined by converged first-principles calculations. We apply the method to monolayer excitons in semiconducting transition metal dichalcogenides and to interlayer excitons in MoSe2/WSe2 heterobilayers and obtain good agreement with recent experimental data. The precision of our method allows us to assign measured g factors of optical peaks to specific transitions in the band structure and also to specific regions of the samples. This revealed the nature of various, previously measured interlayer exciton peaks. We further show that, due to specific optical selection rules, g factors in van der Waals heterostructures are strongly spin and stacking-dependent. The calculation of orbital angular momenta requires the summation over hundreds of bands, indicating that for the considered two-dimensional materials the basis set size is a critical numerical issue. The presented approach can potentially be applied to a wide variety of semiconductors.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000537315100009	Publication Date	2020-06-03
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.7	Times cited		Open Access
	Notes				Approved	Most recent IF: 3.7; 2020 IF: 3.836
	Call Number	UA @ admin @ c:irua:170219			Serial	7944
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	Author	Abdullah, H.M.; da Costa, D.R.; Bahlouli, H.; Chaves, A.; Peeters, F.M.; Van Duppen, B.
	Title	Electron collimation at van der Waals domain walls in bilayer graphene			Type	A1 Journal article
	Year	2019	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	100	Issue	4	Pages	045137
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We show that a domain wall separating single-layer graphene and AA-stacked bilayer graphene (AA-BLG) can be used to generate highly collimated electron beams which can be steered by a magnetic field. Two distinct configurations are studied, namely, locally delaminated AA-BLG and terminated AA-BLG whose terminal edge types are assumed to be either zigzag or armchair. We investigate the electron scattering using semiclassical dynamics and verify the results independently with wave-packet dynamics simulations. We find that the proposed system supports two distinct types of collimated beams that correspond to the lower and upper cones in AA-BLG. Our computational results also reveal that collimation is robust against the number of layers connected to AA-BLG and terminal edges.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000477892800005	Publication Date	2019-07-29
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	10	Open Access
	Notes	; H.M.A. and H.B. acknowledge the support of King Fahd University of Petroleum and Minerals under research group Project No. RG181001. D.R.C and A.C. were financially supported by the Brazilian Council for Research (CNPq) and CAPES foundation. B.V.D. is supported by a postdoctoral fellowship by the Research Foundation Flanders (FWO-Vl). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ admin @ c:irua:161887			Serial	5410
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	Author	Torun, E.; Sahin, H.; Chaves, A.; Wirtz, L.; Peeters, F.M.
	Title	Ab initio and semiempirical modeling of excitons and trions in monolayer TiS3			Type	A1 Journal article
	Year	2018	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	98	Issue	7	Pages	075419
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We explore the electronic and the optical properties of monolayer TiS3, which shows in-plane anisotropy and is composed of a chain-like structure along one of the lattice directions. Together with its robust direct band gap, which changes very slightly with stacking order and with the thickness of the sample, the anisotropic physical properties of TiS3 make the material very attractive for various device applications. In this study, we present a detailed investigation on the effect of the crystal anisotropy on the excitons and the trions of the TiS3 monolayer. We use many-body perturbation theory to calculate the absorption spectrum of anisotropic TiS3 monolayer by solving the Bethe-Salpeter equation. In parallel, we implement and use a Wannier-Mott model for the excitons that takes into account the anisotropic effective masses and Coulomb screening, which are obtained from ab initio calculations. This model is then extended for the investigation of trion states of monolayer TiS3. Our calculations indicate that the absorption spectrum of monolayer TiS3 drastically depends on the polarization of the incoming light, which excites different excitons with distinct binding energies. In addition, the binding energies of positively and the negatively charged trions are observed to be distinct and they exhibit an anisotropic probability density distribution.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000442342100002	Publication Date	2018-08-21
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	10	Open Access
	Notes	; This work was supported by the Flemish Science Foundation (FWO-Vl) and the FLAG-ERA project TRANS-2D-TMD. H.S. acknowledges financial support from TUBITAK under Project No. 117F095. A.C. acknowledges support from the Brazilian Research Council (CNPq), through the PRONEX/FUNCAP and Science Without Borders programs, and from the Lemann Foundation. E.T. and L.W. acknowledge support from the National Research Fund, Luxembourg (IN-TER/ANR/13/20/NANOTMD). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:153721UA @ admin @ c:irua:153721			Serial	5076
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	Author	Cavalcante, L.S.R.; Chaves, A.; Van Duppen, B.; Peeters, F.M.; Reichman, D.R.
	Title	Electrostatics of electron-hole interactions in van der Waals heterostructures			Type	A1 Journal article
	Year	2018	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	97	Issue	12	Pages	125427
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The role of dielectric screening of electron-hole interaction in van der Waals heterostructures is theoretically investigated. A comparison between models available in the literature for describing these interactions is made and the limitations of these approaches are discussed. A simple numerical solution of Poisson's equation for a stack of dielectric slabs based on a transfer matrix method is developed, enabling the calculation of the electron-hole interaction potential at very low computational cost and with reasonable accuracy. Using different potential models, direct and indirect exciton binding energies in these systems are calculated within Wannier-Mott theory, and a comparison of theoretical results with recent experiments on excitons in two-dimensional materials is discussed.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000427983700007	Publication Date	2018-03-21
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	22	Open Access
	Notes	Discussions with A. Chernikov and A. Raja are gratefully acknowledged. This work has been financially supported by CNPq, through the PRONEX/FUNCAP, PQ, and Science Without Borders programs, and the FWO-CNPq bilateral program between Brazil and Flanders. B.V.D. acknowledges support from the Flemish Science Foundation (FWO-Vl) through a postdoctoral fellowship. D.R.R. was supported by NSF CHE-1464802.			Approved	Most recent IF: 3.836
	Call Number	CMT @ cmt @c:irua:150835UA @ admin @ c:irua:150835			Serial	4953
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	Author	Xavier, L.J.P.; Pereira, J.M.; Chaves, A.; Farias, G.A.; Peeters, F.M.
	Title	Topological confinement in graphene bilayer quantum rings			Type	A1 Journal article
	Year	2010	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	96	Issue	21	Pages	212108,1-212108,3
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We find localized electron and hole states in a ring-shaped potential kink in biased bilayer graphene. Within the continuum description, we show that for sharp potential steps the Dirac equation describing carrier states close to the K (or K′) point of the first Brillouin zone can be solved analytically for a circular kink/antikink dot. The solutions exhibit interfacial states which exhibit AharonovBohm oscillations as functions of the height of the potential step and/or the radius of the ring.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000278183200039	Publication Date	2010-05-28
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.411	Times cited	29	Open Access
	Notes	; This work was financially supported by CNPq, under Contract No. NanoBioEstruturas 555183/2005-0, FUNCAP, CAPES, the Bilateral program between Flanders and Brazil, the Belgian Science Policy (IAP) and the Flemish Science Foundation (FWO-Vl). ;			Approved	Most recent IF: 3.411; 2010 IF: 3.841
	Call Number	UA @ lucian @ c:irua:83373			Serial	3675
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	Author	Nascimento, J.S.; da Costa, D.R.; Zarenia, M.; Chaves, A.; Pereira, J.M., Jr.
	Title	Magnetic properties of bilayer graphene quantum dots in the presence of uniaxial strain			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	96	Issue	11	Pages	115428
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Using the tight-binding approach coupled with mean-field Hubbard model, we theoretically study the effect of mechanical deformations on the magnetic properties of bilayer graphene (BLG) quantum dots (QDs). Results are obtained for AA-and AB(Bernal)-stacked BLG QDs, considering different geometries (hexagonal, triangular and square shapes) and edge types (armchair and zigzag edges). In the absence of strain, our results show that (i) the magnetization is affected by taking different dot sizes only for hexagonal BLG QDs with zigzag edges, exhibiting different critical Hubbard interactions, and (ii) the magnetization does not depend on the interlayer hopping energies, except for the geometries with zigzag edges and AA stacking. In the presence of in-plane and uniaxial strain, for all geometries we obtain two different magnetization regimes depending on the applied strain amplitude. The appearance of such different regimes is due to the breaking of layer and sublattice symmetries in BLG QDs.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000411077400008	Publication Date	2017-09-18
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	4	Open Access
	Notes	; This work was financially supported by CNPq, FUNCAP, CAPES Foundation, the Flemish Science Foundation (FWO-Vl), and the Brazilian Program Science Without Borders (CsF). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:146751			Serial	4788
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	Author	de Sousa, G.O.; da Costa, D.R.; Chaves, A.; Farias, G.A.; Peeters, F.M.
	Title	Unusual quantum confined Stark effect and Aharonov-Bohm oscillations in semiconductor quantum rings with anisotropic effective masses			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	95	Pages	205414
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The effects of external electric and magnetic fields on the energy spectrum of quantum rings made out of a bidimensional semiconductor material with anisotropic band structures are investigated within the effective-mass model. The interplay between the effective-mass anisotropy and the radial confinement leads to wave functions that are strongly localized at two diametrically opposite regions where the kinetic energy is lowest due to the highest effective mass. We show that this quantum phenomenon has clear consequences on the behavior of the energy states in the presence of applied in-plane electric fields and out-of-plane magnetic fields. In the former, the quantum confined Stark effect is observed with either linear or quadratic shifts, depending on the direction of the applied field. As for the latter, the usual Aharonov-Bohm oscillations are not observed for a circularly symmetric confining potential, however they can be reinstated if an elliptic ring with an appropriate aspect ratio is chosen.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000401230600007	Publication Date	2017-05-12
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	19	Open Access
	Notes	; This work was financially supported by CNPq under the PRONEX/FUNCAP grants, CAPES Foundation, the Flemish Science Foundation (FWO-Vl), and the Brazilian Program Science Without Borders (CsF). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:143746			Serial	4610
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	Author	da Costa; Zarenia, M.; Chaves, A.; Pereira, J.M., Jr.; Farias, G.A.; Peeters, F.M.
	Title	Hexagonal-shaped monolayer-bilayer quantum disks in graphene : a tight-binding approach			Type	A1 Journal article
	Year	2016	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	94	Issue	94	Pages	035415
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000379502200008	Publication Date	2016-07-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9950;2469-9969;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	11	Open Access
	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
	Call Number	UA @ lucian @ c:irua:134947			Serial	4190
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	Author	Cavalcante, L.S.; Chaves, A.; da Costa, D.R.; Farias, G.A.; Peeters, F.M.
	Title	All-strain based valley filter in graphene nanoribbons using snake states			Type	A1 Journal article
	Year	2016	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	94	Issue	7	Pages	075432
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	A pseudomagnetic field kink can be realized along a graphene nanoribbon using strain engineering. Electron transport along this kink is governed by snake states that are characterized by a single propagation direction. Those pseudomagnetic fields point towards opposite directions in the K and K' valleys, leading to valley polarized snake states. In a graphene nanoribbon with armchair edges this effect results in a valley filter that is based only on strain engineering. We discuss how to maximize this valley filtering by adjusting the parameters that define the stress distribution along the graphene ribbon.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000381889300002	Publication Date	2016-08-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9969; 2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	29	Open Access
	Notes	; Discussions with R. Grassi are gratefully acknowledged. This work was supported by the Brazilian Council for Research (CNPq), under the PRONEX/FUNCAP and Science Without Borders (SWB) programs, CAPES, the Lemann Foundation, and the Flemish Science Foundation (FWO-Vl). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:144667			Serial	4639
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	Author	da Costa, D.R.; Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M.
	Title	Magnetic field dependence of energy levels in biased bilayer graphene quantum dots			Type	A1 Journal article
	Year	2016	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	93	Issue	93	Pages	085401
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000369402400008	Publication Date	2016-02-01
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	22	Open Access
	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
	Call Number	c:irua:131623			Serial	4038
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	Author	Chaves, A.; Mayers, M.Z.; Peeters, F.M.; Reichman, D.R.
	Title	Theoretical investigation of electron-hole complexes in anisotropic two-dimensional materials			Type	A1 Journal article
	Year	2016	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	93	Issue	93	Pages	115314
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Trions and biexcitons in anisotropic two-dimensional materials are investigated within an effective mass theory. Explicit results are obtained for phosphorene and arsenene, materials that share features such as a direct quasiparticle gap and anisotropic conduction and valence bands. Trions are predicted to have remarkably high binding energies and an elongated electron-hole structure with a preference for alignment along the armchair direction, where the effective masses are lower. We find that biexciton binding energies are also notably large, especially for monolayer phosphorene, where they are found to be twice as large as those for typical monolayer transition metal dichalcogenides.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000372715700001	Publication Date	2016-03-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9950;2469-9969;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	33	Open Access
	Notes	; This work has been financially supported by CNPq, through the PRONEX/FUNCAP and Science Without Borders programs, the FWO-CNPq bilateral program between Brazil and Flanders, and the Lemann Foundation. M.Z.M. is supported by a fellowship from the National Science Foundation, under Grant No. DGE-11-44155. ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:133191			Serial	4262
Permanent link to this record



	Author	da Costa, D.R.; Chaves, A.; Sena, S.H.R.; Farias, G.A.; Peeters, F.M.
	Title	Valley filtering using electrostatic potentials in bilayer graphene			Type	A1 Journal article
	Year	2015	Publication	Physical review : B : condensed matter and materials physics	Abbreviated Journal	Phys Rev B
	Volume	92	Issue	92	Pages	045417
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Propagation of an electron wave packet through a quantum point contact (QPC) defined by electrostatic gates in bilayer graphene is investigated. The gates provide a bias between the layers, in order to produce an energy gap. If the gates on both sides of the contact produce the same bias, steps in the electron transmission probability are observed, as in the usual QPC. However, if the bias is inverted on one of the sides of the QPC, only electrons belonging to one of the Dirac valleys are allowed to pass, which provides a very efficient valley filtering.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000358253200009	Publication Date	2015-07-20
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1098-0121;1550-235X;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	47	Open Access
	Notes	; This work was financially supported by CNPq, under PNPD and PRONEX/FUNCAP grants; the CAPES Foundation under ProcessNo. BEX7178/13-1; the Bilateral programme between Flanders and Brazil; the Flemish Science Foundation (FWOVl); and the Brazilian program Science Without Borders (CsF). ;			Approved	Most recent IF: 3.836; 2015 IF: 3.736
	Call Number	c:irua:127152			Serial	3833
Permanent link to this record



	Author	da Costa, D.R.; Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M.
	Title	Energy levels of bilayer graphene quantum dots			Type	A1 Journal article
	Year	2015	Publication	Physical review : B : condensed matter and materials physics	Abbreviated Journal	Phys Rev B
	Volume	92	Issue	92	Pages	115437
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Lancaster, Pa	Editor
	Language		Wos	000361663700003	Publication Date	2015-09-24
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1098-0121; 1550-235x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	21	Open Access
	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
	Call Number	UA @ lucian @ c:irua:128726			Serial	4173
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