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“Three-dimensional electron-hole superfluidity in a superlattice close to room temperature”. Van der Donck M, Conti S, Perali A, Hamilton AR, Partoens B, Peeters FM, Neilson D, Physical Review B 102, 060503 (2020). http://doi.org/10.1103/PHYSREVB.102.060503
Abstract: Although there is strong theoretical and experimental evidence for electron-hole superfluidity in separated sheets of electrons and holes at low T, extending superfluidity to high T is limited by strong two-dimensional fluctuations and Kosterlitz-Thouless effects. We show this limitation can be overcome using a superlattice of alternating electron- and hole-doped semiconductor monolayers. The superfluid transition in a three-dimensional superlattice is not topological, and for strong electron-hole pair coupling, the transition temperature T-c can be at room temperature. As a quantitative illustration, we show T-c can reach 270 K for a superfluid in a realistic superlattice of transition metal dichalcogenide monolayers.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 8
DOI: 10.1103/PHYSREVB.102.060503
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“Two-dimensional graphitic carbon nitrides: strain-tunable ferromagnetic ordering”. Bafekry A, Neek-Amal M, Peeters FM, Physical Review B 101, 165407 (2020). http://doi.org/10.1103/PHYSREVB.101.165407
Abstract: Using first-principle calculations, we systematically study strain tuning of the electronic properties of two- dimensional graphitic carbon nitride nanosheets with empirical formula CnNm. We found the following: (i) the ferromagnetic ordered state in the metal-free systems (n, m) = (4,3), (10,9), and (14,12) remains stable in the presence of strain of about 6%. However, the system (9,7) loses its ferromagnetic ordering when increasing strain. This is due to the presence of topological defects in the (9,7) system, which eliminates the asymmetry between spin up and spin down of the p(z) orbitals when strain is applied. (ii) By applying uniaxial strain, a band gap opens in systems which are initially gapless. (iii) In semiconducting systems which have an initial gap of about 1 eV, the band gap is closed with applying uniaxial strain.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 27
DOI: 10.1103/PHYSREVB.101.165407
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“Band flattening in buckled monolayer graphene”. Milovanović, SP, Andelkovic M, Covaci L, Peeters FM, Physical Review B 102, 245427 (2020). http://doi.org/10.1103/PHYSREVB.102.245427
Abstract: The strain fields of periodically buckled graphene induce a periodic pseudomagnetic field (PMF) that modifies the electronic band structure. From the geometry, amplitude, and period of the periodic pseudomagnetic field, we determine the necessary conditions to access the regime of correlated phases by examining the band flattening. As compared to twisted bilayer graphene the proposed system has the advantages that (1) only a single layer of graphene is needed, (2) one is not limited to hexagonal superlattices, and (3) narrower flat bandwidth and larger separation between flat bands can be induced. We, therefore, propose that periodically strained graphene single layers can become a platform for the exploration of exotic many-body phases.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 27
DOI: 10.1103/PHYSREVB.102.245427
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“Sorting the modes contributing to guidance in strain-induced graphene waveguides”. Villegas CEP, Tavares MRS, Hai G-Q, Peeters FM, New journal of physics 15, 023015 (2013). http://doi.org/10.1088/1367-2630/15/2/023015
Abstract: We propose a simple way of probing the number of modes contributing to the channeling in graphene waveguides which are formed by a gauge potential produced by mechanical strain. The energy mode structure for both homogeneous and non-homogeneous strain regimes is carefully studied using the continuum description of the Dirac equation. We found that high strain values privilege negative (instead of positive) group velocities throughout the guidance, sorting the types of modes flowing through it. We also show how the effect of a substrate-induced gap competes against the strain.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 7
DOI: 10.1088/1367-2630/15/2/023015
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“Analysis of pattern formation in systems with competing range interactions”. Zhao HJ, Misko VR, Peeters FM, New journal of physics 14, 063032 (2012). http://doi.org/10.1088/1367-2630/14/6/063032
Abstract: We analyzed pattern formation and identified various morphologies in a system of particles interacting through a non-monotonic potential with a competing range interaction characterized by a repulsive core (r < r(c)) and an attractive tail (r > r(c)), using molecular-dynamics simulations. Depending on parameters, the interaction potential models the inter-particle interaction in various physical systems ranging from atoms, molecules and colloids to vortices in low kappa type-II superconductors and in recently discovered 'type-1.5' superconductors. We constructed a 'morphology diagram' in the plane 'critical radius r(c)-density n' and proposed a new approach to characterizing the different types of patterns. Namely, we elaborated a set of quantitative criteria in order to identify the different pattern types, using the radial distribution function (RDF), the local density function and the occupation factor.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 45
DOI: 10.1088/1367-2630/14/6/063032
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“Composite vortex ordering in superconducting films with arrays of blind holes”. Berdiyorov GR, Milošević, MV, Peeters FM, New journal of physics 11, 013025 (2009). http://doi.org/10.1088/1367-2630/11/1/013025
Abstract: The pinning properties of a superconducting thin film with a square array of blind holes are studied using the nonlinear GinzburgLandau theory. Although blind holes provide a weaker pinning potential than holes (also called antidots), several novel vortex structures are predicted for different size and thickness of the blind holes. Orientational dimer and trimer vortex states as well as concentric vortex shells can nucleate in the blind holes. In addition, we predict the stabilization of giant vortices that may be located both in the pinning centers and/or at the interstitial sites, as well as the combination of giant vortices with sets of individual vortices. For large blind holes, local vortex shell structures inside the blind holes may transfer their symmetry to interstitial vortices as well. The subtle interplay of shell formation and traditional Abrikosov vortex lattices inside the blind holes is also studied for different numbers of trapped vortices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 33
DOI: 10.1088/1367-2630/11/1/013025
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“Magnetic Kronig-Penney model for Dirac electrons in single-layer graphene”. Masir MR, Vasilopoulos P, Peeters FM, New journal of physics 11, 095009 (2009). http://doi.org/10.1088/1367-2630/11/9/095009
Abstract: he properties of Dirac electrons in a magnetic superlattice (SL) on graphene consisting of very high and thin (δ-function) barriers are investigated. We obtain the energy spectrum analytically and study the transmission through a finite number of barriers. The results are contrasted with those for electrons described by the Schrödinger equation. In addition, a collimation of an incident beam of electrons is obtained along the direction perpendicular to that of the SL. We also highlight an analogy with optical media in which the refractive index varies in space.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 89
DOI: 10.1088/1367-2630/11/9/095009
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“Vortex matter in oblate mesoscopic superconductors with a hole: broken symmetry vortex states and multi-vortex entry”. Xu B, Milošević, MV, Peeters FM, New journal of physics 11, 013020 (2009). http://doi.org/10.1088/1367-2630/11/1/013020
Abstract: Using three-dimensional (3D) numerical discretization of the GinzburgLandau (GL) equations, we investigate the superconducting state of a sphere with a piercing hole in the presence of a magnetic field. In the case of samples with central perforation, in axially applied homogeneous magnetic field, we realized unconventional vortex states of broken symmetry due to complex, 3D competing interactions, which depend on the GL parameter ê. For certain sizes of the sample, non-hysteretic multi-vortex entry and exit is predicted with the non-existence of some vorticities as stable states. In a tilted magnetic field, we studied the gradual transformation of 3D flux patterns into 1D vortex chains, where vortices align along the perforation, and the evolvement of the multi-vortex entry as well. We analyze the flux-guiding ability of the hole in a tilted field, which leads to fractional flux response in magnetization M(H) curves.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 8
DOI: 10.1088/1367-2630/11/1/013020
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“A non-Maxwellian kinetic approach for charging of dust particles in discharge plasmas”. Alexandrov AL, Schweigert IV, Peeters FM, New journal of physics 10, 093025 (2008). http://doi.org/10.1088/1367-2630/10/9/093025
Abstract: Nanoparticle charging in a capacitively coupled radio frequency discharge in argon is studied using a particle in cell Monte Carlo collisions method. The plasma parameters and dust potential were calculated self-consistently for different unmovable dust profiles. A new method for definition of the dust floating potential is proposed, based on the information about electron and ion energy distribution functions, obtained during the kinetic simulations. This approach provides an accurate balance of the electron and ion currents on the dust particle surface and allows us to precisely calculate the dust floating potential. A comparison of the obtained floating potentials with the results of the traditional orbital motion limit (OML) theory shows that in the presence of the ion resonant charge exchange collisions, even when the OML approximation is valid, its results are correct only in the region of a weak electric field, where the ion drift velocity is much smaller than the thermal one. With increasing ion drift velocity, the absolute value of the calculated dust potential becomes significantly smaller than the theory predicts. This is explained by a non-Maxwellian shape of the ion energy distribution function for the case of fast ion drift.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 19
DOI: 10.1088/1367-2630/10/9/093025
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“Structural and dynamical aspects of small three-dimensional spherical Coulomb clusters”. Apolinario SWS, Partoens B, Peeters FM, New journal of physics 9, 283 (2007). http://doi.org/10.1088/1367-2630/9/8/283
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 44
DOI: 10.1088/1367-2630/9/8/283
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“Structural, dynamical and melting properties of two-dimensional clusters of complex plasmas”. Kong M, Partoens B, Peeters FM, New journal of physics 5, 23 (2003). http://doi.org/10.1088/1367-2630/5/1/323
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 67
DOI: 10.1088/1367-2630/5/1/323
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“Two-dimensional oxygen functionalized honeycomb and zigzag dumbbell silicene with robust Dirac cones”. Chen X, Li L, Peeters FM, Sanyal B, New Journal Of Physics 23, 023007 (2021). http://doi.org/10.1088/1367-2630/ABDB6E
Abstract: Dumbbell-like structures are recently found to be energetically favored in group IV two-dimensional (2D) materials, exhibiting rich physics and many interesting properties. In this paper, using first-principles calculations, we have investigated the oxidized form of the hexagonal honeycomb (ODB-h) and zigzag dumbbell silicene (ODB-z). We confirm that both oxidization processes are energetically favorable, and their phonon spectra further demonstrate the dynamic stability. Contrary to the pristine dumbbell silicene structures (PDB-h and PDB-z silicene), these oxidized products ODB-h and ODB-z silicene are both semimetals with Dirac cones at the Fermi level. The Dirac cones of ODB-h and ODB-z silicene are at the K point and between Y and Gamma points respectively, possessing high Fermi velocities of 3.1 x 10(5) m s(-1) (ODB-h) and 2.9-3.4 x 10(5) m s(-1) (ODB-z). The origin of the Dirac cones is further explained by tight-binding models. The semimetallic properties of ODB-h and ODB-z are sensitive to compression due to the self-absorption effect, but quite robust against the tensile strain. These outstanding properties make oxidized dumbbell silicene a promising material for quantum computing and high-speed electronic devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 2
DOI: 10.1088/1367-2630/ABDB6E
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“Topological phase transitions and Majorana zero modes in DNA double helix coupled to s-wave superconductors”. Chen Q, Guo A-M, Liu J, Peeters FM, Sun Q-F, New Journal Of Physics 23, 093047 (2021). http://doi.org/10.1088/1367-2630/AC2711
Abstract: Topological properties of a double-stranded DNA (dsDNA) proximity-coupled by an s-wave superconductor are investigated, in which the energy spectra and the differential conductance are calculated within the framework of tight-binding approximation. Our results indicate that this dsDNA-superconductor system hosts Majorana zero modes (MZMs) when the Zeeman field is perpendicular to the helix axis, whereas no MZM could be observed when the Zeeman field is parallel to the helix axis, in sharp contrast to previous studies on nanowires including single-stranded DNA. In particular, two topological phase transitions could take place in the dsDNA-superconductor system by changing the Zeeman field, one from a topological trivial phase to a topological nontrivial phase with one pair of MZMs in small Zeeman field regime, and the other from a phase with one pair of MZMs to a phase with two pairs of MZMs by further increasing the Zeeman field. In the presence of a gate field normal to the helix axis, the topological nontrivial phase with two pairs of MZMs can transform into the phase with one pair of MZMs. The topological phase with one pair of MZMs is more stable and robust against Anderson disorder.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 7
DOI: 10.1088/1367-2630/AC2711
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“Coulomb impurity on a Dice lattice : atomic collapse and bound states”. Wang J, Van Pottelberge R, Zhao W-S, Peeters FM, Physical review B 105, 035427 (2022). http://doi.org/10.1103/PHYSREVB.105.035427
Abstract: The modification of the quantum states in a Dice lattice due to a Coulomb impurity are investigated. The energy-band structure of a pristine Dice lattice consists of a Dirac cone and a flat band at the Dirac point. We use the tight-binding formalism and find that the flat band states transform into a set of discrete bound states whose electron density is localized on a ring around the impurity mainly on two of the three sublattices. Its energy is proportional to the strength of the Coulomb impurity. Beyond a critical strength of the Coulomb potential atomic collapse states appear that have some similarity with those found in graphene with the difference that the flat band states contribute with an additional ringlike electron density that is spatially decoupled from the atomic collapse part. At large value of the strength of the Coulomb impurity the flat band bound states anticross with the atomic collapse states.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 3
DOI: 10.1103/PHYSREVB.105.035427
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“Ferromagnetism with in-plane magnetization, Dirac spin-gapless semiconducting properties, and tunable topological states in two-dimensional rare-earth metal dinitrides”. Yu Y, Chen X, Liu X, Li J, Sanyal B, Kong X, Peeters FM, Li L, Physical review B 105, 024407 (2022). http://doi.org/10.1103/PHYSREVB.105.024407
Abstract: Since the successful synthesis of bulk single crystals MoN2 and ReN2, which have a layered structure, transition-metal dinitrides have attracted considerable attention in recent years. Here, we focus on rare-earth metal (Rem) elements, and propose seven stable Rem dinitride monolayers with a 1T structure, namely, 1T-RemN2. We use first-principles calculations, and find that these monolayers have a ferromagnetic ground state with in-plane magnetization. Without spin-orbit coupling (SOC), the band structures are spin-polarized with Dirac points at the Fermi level. Remarkably, the 1T-LuN2 monolayer exhibits an isotropic magnetocrystalline anisotropy energy in the xy plane with in-plane magnetization, indicating easy tunability of the magnetization direction. When rotating the magnetization vector in the xy plane, we propose a model that accurately describes the variation of the SOC band gap and the two possible topological states (Weyl-like semimetal and Chern insulator states) whose properties are tunable. The Weyl-like semimetal state is a critical point between the two Chern insulator states with opposite sign of the Chern numbers (+/- 1). The nontrivial band gap (up to 60.3 meV) and the Weyl-like semimetal state are promising for applications in spintronic devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 13
DOI: 10.1103/PHYSREVB.105.024407
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“Anisotropic and tunable optical conductivity of a two-dimensional semi-Dirac system in the presence of elliptically polarized radiation”. Zhang HY, Xiao YM, N Li Q, Ding L, Van Duppen B, Xu W, Peeters FM, Physical review B 105, 115423 (2022). http://doi.org/10.1103/PHYSREVB.105.115423
Abstract: We investigate the effect of ellipticity ratio of the polarized radiation field on optoelectronic properties of a two-dimensional (2D) semi-Dirac (SD) system. The optical conductivity is calculated within the energy balance equation approach derived from the semiclassical Boltzmann equation. We find that there exists the anisotropic optical absorption induced via both the intra-and interband electronic transition channels in the perpendicular xx and yy directions. Furthermore, we examine the effects of the ellipticity ratio, the temperature, the carrier density, and the band-gap parameter on the optical conductivity of the 2D SD system placed in transverse and vertical directions, respectively. It is shown that the ellipticity ratio, temperature, carrier density, and band-gap parameter can play the important roles in tuning the strength, peak position, and shape of the optical conductivity spectrum. The results obtained from this study indicate that the 2D SD system can be a promising anisotropic and tunable optical and optoelectronic material for applications in innovative 2D optical and optoelectronic devices, which are active in the infrared and terahertz bandwidths.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 3
DOI: 10.1103/PHYSREVB.105.115423
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“Controlling the hybridization gap and transport in a thin-film topological insulator : effect of strain, and electric and magnetic field”. Shafiei M, Fazileh F, Peeters FM, Milošević, MV, Physical review B 106, 035119 (2022). http://doi.org/10.1103/PHYSREVB.106.035119
Abstract: In a thin-film topological insulator (TI), the edge states on two surfaces may couple by quantum tunneling, opening a gap known as the hybridization gap. Controlling the hybridization gap and transport has a variety of potential uses in photodetection and energy-harvesting applications. In this paper, we report the effect of strain, and electric and magnetic field, on the hybridization gap and transport in a thin Bi2Se3 film, investigated within the tight-binding theoretical framework. We demonstrate that vertical compression decreases the hybridization gap, as does tensile in-plane strain. Applying an electric field breaks the inversion symmetry and leads to a Rashba-like spin splitting proportional to the electric field, hence closing and reopening the gap. The influence of a magnetic field on thin-film TI is also discussed, starting from the role of an out-of-plane magnetic field on quantum Hall states. We further demonstrate that the hybridization gap can be controlled by an in-plane magnetic field, and that by applying a sufficiently strong field a quantum phase transition from an insulator to a semimetal can be achieved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 7
DOI: 10.1103/PHYSREVB.106.035119
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“Isolated and hybrid bilayer graphene quantum rings”. Mirzakhani M, da Costa DR, Peeters FM, Physical review B 105, 115430 (2022). http://doi.org/10.1103/PHYSREVB.105.115430
Abstract: Using the continuum model, we investigate the electronic properties of two types of bilayer graphene (BLG) quantum ring (QR) geometries: (i) An isolated BLG QR and (ii) a monolayer graphene (MLG) with a QR put on top of an infinite graphene sheet (hybrid BLG QR). Solving the Dirac-Weyl equation in the presence of a perpendicular magnetic field and applying the infinite mass boundary condition at the ring boundaries, we obtain analytical results for the energy levels and corresponding wave spinors for both structures. In the case of isolated BLG QR, we observe a sizable and magnetically tunable band gap which agrees with the tight-binding transport simulations. Our analytical results also show the intervalley symmetry EeK (m) = ???EK??? h (m) between the electron (e) and the hole (h) states (m is the angular momentum quantum number) for the energy spectrum of the isolated BLG QR. The presence of interface boundary in a hybrid BLG QR modifies drastically the energy levels as compared with that of an isolated BLG QR. Its energy levels are tunable from MLG dot to isolated BLG QR and to MLG Landau energy levels as the magnetic field is varied. Our predictions can be verified experimentally using different techniques such as by magnetotransport measurements.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 4
DOI: 10.1103/PHYSREVB.105.115430
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“Tunneling properties in α-T₃, lattices : effects of symmetry-breaking terms”. Cunha SM, da Costa DR, Pereira JM Jr, Costa Filho RN, Van Duppen B, Peeters FM, Physical review B 105, 165402 (2022). http://doi.org/10.1103/PHYSREVB.105.165402
Abstract: The alpha-T3 lattice model interpolates a honeycomb (graphene-like) lattice and a T3 (also known as dice) lattice via the parameter alpha. These lattices are made up of three atoms per unit cell. This gives rise to an additional dispersionless flat band touching the conduction and valence bands. Electrons in this model are analogous to Dirac fermions with an enlarged pseudospin, which provides unusual tunneling features like omnidirectional Klein tunneling, also called super-Klein tunneling (SKT). However, it is unknown how small deviations in the equivalence between the atomic sites, i.e., variations in the alpha parameter, and the number of tunnel barriers changes the transmission properties. Moreover, it is interesting to learn how tunneling occurs through regions where the energy spectrum changes from linear with a middle flat band to a hyperbolic dispersion. In this paper we investigate these properties, its dependence on the number of square barriers and the alpha parameter for either gapped and gapless cases. Furthermore, we compare these results to the case where electrons tunnel from a region with linear dispersion to a region with a bandgap. In the latter case, contrary to tunneling through a potential barrier, the SKT is no longer observed. Finally, we find specific cases where transmission is allowed due to a symmetry breaking of sublattice equivalence.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
DOI: 10.1103/PHYSREVB.105.165402
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“Influence of neutron irradiation on X-ray diffraction, Raman spectrum and photoluminescence from pyrolytic and hot-pressed hexagonal boron nitride”. Zhou S, Xu W, Xiao Y, Xiao H, Zhang J, Wang Z, He G, Liu J, Li Y, Peeters FM, Journal of luminescence 263, 120118 (2023). http://doi.org/10.1016/J.JLUMIN.2023.120118
Abstract: Hexagonal boron nitride (hBN) is considered as an ideal semiconductor material for solid-state neutron detector, owing to its large neutron scattering section because of the low atomic number of B and excellent physical properties. Here we study the influence of neutron irradiation on crystal structure and on intermediate energy state (IMES) levels induced by the presence of impurities and defects in hBN. Large-size and thick pyrolytic and hot-pressed hBN (PBN and HBN) samples, which can be directly applied for neutron detector devices, are prepared and bombarded by neutrons with different irradiation fluences. The SEM and TEM are used to observe the sample difference of PBN and HBN. X-ray diffraction and Raman spectroscopy are applied to examine the influence of neutron irradiation on lattice structures along different crystal directions of PBN and HBN samples. Photoluminescence (PL) is employed to study the effect of neutron irradiation on IMESs in these samples. We find that the neutron irradiation does not alter the in-plane lattice structures of both PBN and HBN samples, but it can release the inter-layer tensions induced by sample growth of the PBN samples. Interestingly and surprisingly, the neutron irradiation does not affect the IMES levels responsible for PL generation, where PL is attributed mainly from phonon-assisted radiative electron-hole coupling for both PBN and HBN samples. Furthermore, the results indicate that the neutron irradiation can weaken the effective carrier-phonon coupling and exciton transitions in PBN and HBN samples. Overall, both PBN and HBN samples show some degree of the resistance to neutron irradiation in terms of these basic physical properties. The interesting and important findings from this work can help us to gain an in-depth understanding of the influence of neutron irradiation on basic physical properties of hBN materials. These effects can be taken into account when designing and applying the hBN materials for neutron detectors.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.6
Times cited: 1
DOI: 10.1016/J.JLUMIN.2023.120118
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“Vacancy clustering effect on the electronic and transport properties of bilayer graphene nanoribbons”. Miranda LP, da Costa DR, Peeters FM, Costa Filho RN, Nanotechnology 34, 055706 (2023). http://doi.org/10.1088/1361-6528/AC9F50
Abstract: Experimental realizations of two-dimensional materials are hardly free of structural defects such as e.g. vacancies, which, in turn, modify drastically its pristine physical defect-free properties. In this work, we explore effects due to point defect clustering on the electronic and transport properties of bilayer graphene nanoribbons, for AA and AB stacking and zigzag and armchair boundaries, by means of the tight-binding approach and scattering matrix formalism. Evident vacancy concentration signatures exhibiting a maximum amplitude and an universality regardless of the system size, stacking and boundary types, in the density of states around the zero-energy level are observed. Our results are explained via the coalescence analysis of the strong sizeable vacancy clustering effect in the system and the breaking of the inversion symmetry at high vacancy densities, demonstrating a similar density of states for two equivalent degrees of concentration disorder, below and above the maximum value.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.5
Times cited: 1
DOI: 10.1088/1361-6528/AC9F50
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“Tuning the polarized quantum phonon transmission in graphene nanoribbons”. Scuracchio P, Dobry A, Costamagna S, Peeters FM, Nanotechnology 26, 305401 (2015). http://doi.org/10.1088/0957-4484/26/30/305401
Abstract: We propose systems that allow a tuning of the phonon transmission function T(omega) in graphene nanoribbons by using C-13 isotope barriers, antidot structures, and distinct boundary conditions. Phonon modes are obtained by an interatomic fifth-nearest neighbor force-constant model (5NNFCM) and T(omega) is calculated using the non-equilibrium Green's function formalism. We show that by imposing partial fixed boundary conditions it is possible to restrict contributions of the in-plane phonon modes to T(omega) at low energy. On the contrary, the transmission functions of out-of-plane phonon modes can be diminished by proper antidot or isotope arrangements. In particular, we show that a periodic array of them leads to sharp dips in the transmission function at certain frequencies omega(nu) which can be pre-defined as desired by controlling their relative distance and size. With this, we demonstrated that by adequate engineering it is possible to govern the magnitude of the ballistic transmission functions T(omega) in graphene nanoribbons. We discuss the implications of these results in the design of controlled thermal transport at the nanoscale as well as in the enhancement of thermo-electric features of graphene-based materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 5
DOI: 10.1088/0957-4484/26/30/305401
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“Quantum tunneling through graphene nanorings”. Wu Z, Zhang ZZ, Chang K, Peeters FM, Nanotechnology 21, 185201 (2010). http://doi.org/10.1088/0957-4484/21/18/185201
Abstract: We investigate theoretically quantum transport through graphene nanorings in the presence of a perpendicular magnetic field. Our theoretical results demonstrate that the graphene nanorings behave like a resonant tunneling device, contrary to the Aharonov-Bohm oscillations found in conventional semiconductor rings. The resonant tunneling can be tuned by the Fermi energy, the size of the central part of the graphene nanorings and the external magnetic field.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 34
DOI: 10.1088/0957-4484/21/18/185201
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“Crystallographic plane tuning of charge and spin transport in semiconductor quantum wires”. Wang M, Chang K, Wang LG, Dai N, Peeters FM, Nanotechnology 20, 365202 (2009). http://doi.org/10.1088/0957-4484/20/36/365202
Abstract: We investigate theoretically the charge and spin transport in quantum wires grown along different crystallographic planes in the presence of the Rashba spinorbit interaction (RSOI) and the Dresselhaus spinorbit interaction (DSOI). We find that changing the crystallographic planes leads to a variation of the anisotropy of the conductance due to a different interplay between the RSOI and DSOI, since the DSOI is induced by bulk inversion asymmetry, which is determined by crystallographic plane. This interplay depends sensitively on the crystallographic planes, and consequently leads to the anisotropic charge and spin transport in quantum wires embedded in different crystallographic planes.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 14
DOI: 10.1088/0957-4484/20/36/365202
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“Resonant tunneling through S- and U-shaped graphene nanoribbons”. Zhang ZZ, Wu ZH, Chang K, Peeters FM, Nanotechnology 20, 415203 (2009). http://doi.org/10.1088/0957-4484/20/41/415203
Abstract: We theoretically investigate resonant tunneling through S- and U-shaped nanostructured graphene nanoribbons. A rich structure of resonant tunneling peaks is found emanating from different quasi-bound states in the middle region. The tunneling current can be turned on and off by varying the Fermi energy. Tunability of resonant tunneling is realized by changing the width of the left and/or right leads and without the use of any external gates.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 32
DOI: 10.1088/0957-4484/20/41/415203
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“Effects of lateral asymmetry on electronic structure of strained semiconductor nanorings in a magnetic field”. Milošević, MM, Tadić, M, Peeters FM, Nanotechnology 19 (2008). http://doi.org/10.1088/0957-4484/19/45/455401
Abstract: The influence of lateral asymmetry on the electronic structure and optical transitions in elliptical strained InAs nanorings is analyzed in the presence of a perpendicular magnetic field. Two-dimensional rings are assumed to have elliptical inner and outer boundaries oriented in mutually orthogonal directions. The influence of the eccentricity of the ring on the energy levels is analyzed. For large eccentricity of the ring, we do not find any AharonovBohm effect, in contrast to circular rings. Rather, the single-particle states of the electrons and the holes are localized as in two laterally coupled quantum dots formed in the lobes of the nanoring. Our work indicates that the control of shape is important for the existence of the AharonovBohm effect in semiconductor nanorings.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 11
DOI: 10.1088/0957-4484/19/45/455401
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“Transport of magnetic edge states in a quantum wire exposed to a non-homogeneous magnetic field”. Badalyan SM, Peeters FM, Nanotechnology 12, 570 (2001). http://doi.org/10.1088/0957-4484/12/4/340
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 5
DOI: 10.1088/0957-4484/12/4/340
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“Characterization of the size and position of electron-hole puddles at a graphene p-n junction”. Milovanovic SP, Peeters FM, Nanotechnology 27, 105203 (2016). http://doi.org/10.1088/0957-4484/27/10/105203
Abstract: The effect of an electron-hole puddle on the electrical transport when governed by snake states in a bipolar graphene structure is investigated. Using numerical simulations we show that information on the size and position of the electron-hole puddle can be obtained using the dependence of the conductance on magnetic field and electron density of the gated region. The presence of the scatterer disrupts snake state transport which alters the conduction pattern. We obtain a simple analytical formula that connects the position of the electron-hole puddle with features observed in the conductance. The size of the electron-hole puddle is estimated from the magnetic field and gate potential that maximizes the effect of the puddle on the electrical transport.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 3
DOI: 10.1088/0957-4484/27/10/105203
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“Exciton pumping across type-I gallium chalcogenide heterojunctions”. Cai H, Kang J, Sahin H, Chen B, Suslu A, Wu K, Peeters F, Meng X, Tongay S, Nanotechnology 27, 065203 (2016). http://doi.org/10.1088/0957-4484/27/6/065203
Abstract: Quasi-two-dimensional gallium chalcogenide heterostructures are created by transferring exfoliated few-layer GaSe onto bulk GaTe sheets. Luminescence spectroscopy measurements reveal that the light emission from underlying GaTe layers drastically increases on heterojunction regions where GaSe layers make contact with the GaTe. Density functional theory (DFT) and band offset calculations show that conduction band minimum (CBM) (valance band maximum (VBM)) values of GaSe are higher (lower) in energy compared to GaTe, forming type-I band alignment at the interface. Consequently, GaSe layers provide photo-excited electrons and holes to GaTe sheets through relatively large built-in potential at the interface, increasing overall exciton population and light emission from GaTe. Observed results are not specific to the GaSe/GaTe system but observed on GaS/GaSe heterolayers with type-I band alignment. Observed experimental findings and theoretical studies provide unique insights into interface effects across dissimilar gallium chalcogenides and offer new ways to boost optical performance by simple epitaxial coating.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 15
DOI: 10.1088/0957-4484/27/6/065203
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“Controlled growth mechanism of poly (3-hexylthiophene) nanowires”. Kiymaz D, Yagmurcukardes M, Tomak A, Sahin H, Senger RT, Peeters FM, Zareie HM, Zafer C, Nanotechnology 27, 455604 (2016). http://doi.org/10.1088/0957-4484/27/45/455604
Abstract: Synthesis of 1D-polymer nanowires by a self-assembly method using marginal solvents is an attractive technique. While the formation mechanism is poorly understood, this method is essential in order to control the growth of nanowires. Here we visualized the time-dependent assembly of poly (3-hexyl-thiophene-2,5-diyl) (P3HT) nanowires by atomic force microscopy and scanning tunneling microscopy. The assembly of P3HT nanowires was carried out at room temperature by mixing cyclohexanone (CHN), as a poor solvent, with polymer solution in 1,2-dichlorobenzene (DCB). Both pi-pi stacking and planarization, obtained at the mix volume ratio of P3HT (in DCB):CHN (10:7), were considered during the investigation. We find that the length of nanowires was determined by the ordering of polymers in the polymer repetition direction. Additionally, our density functional theory calculations revealed that the presence of DCB and CHN molecules that stabilize the structural distortions due to tail group of polymers was essential for the core-wire formation.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 24
DOI: 10.1088/0957-4484/27/45/455604
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