|
“A demonstration of donor passivation through direct formation of V-As-i complexes in As-doped Ge1-XSnx”. Khanam A, Vohra A, Slotte J, Makkonen I, Loo R, Pourtois G, Vandervorst W, Journal Of Applied Physics 127, 195703 (2020). http://doi.org/10.1063/5.0003999
Abstract: Positron annihilation spectroscopy in the Doppler and coincidence Doppler mode was applied on Ge1 xSnx epitaxial layers, grown by chemical vapor deposition with different total As concentrations (1019-1021 cm3), high active As concentrations (1019 cm3), and similar Sn concentrations (5.9%-6.4%). Positron traps are identified as mono-vacancy complexes. Vacancy-As complexes, V-Asi, formed during the growth were studied to deepen the understanding of the electrical passivation of the Ge1 xSnx:As epilayers. Larger monovacancy complexes, V-Asi (i 2), are formed as the As doping increases. The total As concentration shows a significant impact on the saturation of the number of As atoms (i 1/4 4) around the vacancies in the sample epilayers. The presence of V-Asi complexes decreases the dopant activation in the Ge1 xSnx:As epilayers. Furthermore, the presence of Sn failed to hinder the formation of larger V-Asi complexes and thus failed to reduce the donor-deactivation.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.2
DOI: 10.1063/5.0003999
|
|
|
“Asymmetric versus symmetric HgTe/CdxHg1-x Te double quantum wells: Bandgap tuning without electric field”. Topalovic DB, Arsoski VV, Tadic MZ, Peeters FM, Journal Of Applied Physics 128, 064301 (2020). http://doi.org/10.1063/5.0016069
Abstract: We investigate the electron states in double asymmetric HgTe / Cd x Hg 1 – x Te quantum wells grown along the [ 001 ] direction. The subbands are computed by means of the envelope function approximation applied to the eight-band Kane k . mml:mspace width=“.1em”mml:mspace p model. The asymmetry of the confining potential of the double quantum wells results in a gap opening, which is absent in the symmetric system where it can only be induced by an applied electric field. The bandgap and the subbands are affected by spin-orbit coupling, which is a consequence of the asymmetry of the confining potential. The electron-like and hole-like states are mainly confined in different quantum wells, and the enhanced hybridization between them opens a spin-dependent hybridization gap at a finite in-plane wavevector. We show that both the ratio of the widths of the two quantum wells and the mole fraction of the C d x H g 1 – x Te barrier control both the energy gap between the hole-like states and the hybridization gap. The energy subbands are shown to exhibit inverted ordering, and therefore, a nontrivial topological phase could emerge in the system.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.2
Times cited: 4
DOI: 10.1063/5.0016069
|
|
|
“Investigation of voltage effect on reaction mechanisms in capacitively coupled N-2 discharges”. Liang Y-S, Liu Y-X, Zhang Y-R, Wang Y-N, Journal Of Applied Physics 127, 133301 (2020). http://doi.org/10.1063/1.5143821
Abstract: A systematic investigation of voltage effect on the plasma parameters, especially the species densities and chemical reaction mechanisms, in the capacitive N-2 discharges is performed by employing a two-dimensional self-consistent fluid model. The validity of the numerical model is first demonstrated by the qualitative agreement of the calculated and experimental results. Then, the densities, production mechanisms, and loss mechanisms of species from simulation are examined at various voltages. It is found that all the species densities increase monotonically with the voltage, whereas their spatial profiles at lower voltages are quite different from those at higher voltages. The electrons and Nthorn 2 ions are mainly generated by the electron impact ionization of N-2 gas, while the Nthorn ions, whose density is one or two orders of magnitude lower, are mostly formed by the ionization of N atoms. The electron impact dissociation of N-2 gas dominates the generation of N atoms, which are mostly destroyed for the Nthorn ion production. As for the excited N-2 levels, the level conversion processes play a very important role in their production and depletion mechanisms, except for the electron impact excitation of the ground state N-2 molecules. Published under license by AIP Publishing.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.2
DOI: 10.1063/1.5143821
|
|
|
“Optical absorption window in Na₃Bi based three-dimensional Dirac electronic system”. Li QN, Xu W, Xiao YM, Ding L, Van Duppen B, Peeters FM, Journal Of Applied Physics 128, 155707 (2020). http://doi.org/10.1063/5.0022669
Abstract: We present a detailed theoretical study of the optoelectronic properties of a Na3Bi based three-dimensional Dirac electronic system (3DDES). The optical conductivity is evaluated using the energy-balance equation derived from a Boltzmann equation, where the electron Hamiltonian is taken from a simplified k . p approach. We find that for short-wavelength irradiation, the optical absorption in Na3Bi is mainly due to inter-band electronic transitions. In contrast to the universal optical conductance observed for graphene, the optical conductivity for Na3Bi based 3DDES depends on the radiation frequency but not on temperature, carrier density, and electronic relaxation time. In the radiation wavelength regime of about 5 mu m, < lambda < 200 mu m, an optical absorption window is found. This is similar to what is observed in graphene. The position and width of the absorption window depend on the direction of the light polarization and sensitively on temperature, carrier density, and electronic relaxation time. Particularly, we demonstrate that the inter-band optical absorption channel can be switched on and off by applying the gate voltage. This implies that similar to graphene, Na3Bi based 3DDES can also be applied in infrared electro-optical modulators. Our theoretical findings are helpful in gaining an in-depth understanding of the basic optoelectronic properties of recently discovered 3DDESs.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.2
Times cited: 1
DOI: 10.1063/5.0022669
|
|
|
“Tunable magnetic focusing using Andreev scattering in superconductor-graphene hybrid devices”. Chaves A, Moura VN, Linard FJA, Covaci L, Milošević, MV, Journal Of Applied Physics 128, 124303 (2020). http://doi.org/10.1063/5.0020392
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.2
Times cited: 1
DOI: 10.1063/5.0020392
|
|
|
“Machine learning approach to constructing tight binding models for solids with application to BiTeCl”. Nakhaee M, Ketabi SA, Peeters FM, Journal Of Applied Physics 128, 215107 (2020). http://doi.org/10.1063/5.0023980
Abstract: Finding a tight-binding (TB) model for a desired solid is always a challenge that is of great interest when, e.g., studying transport properties. A method is proposed to construct TB models for solids using machine learning (ML) techniques. The approach is based on the LCAO method in combination with Slater-Koster (SK) integrals, which are used to obtain optimal SK parameters. The lattice constant is used to generate training examples to construct a linear ML model. We successfully used this method to find a TB model for BiTeCl, where spin-orbit coupling plays an essential role in its topological behavior.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.2
Times cited: 10
DOI: 10.1063/5.0023980
|
|
|
“2D quantum materials : magnetism and superconductivity”. Milošević, MV, Mandrus D, Journal Of Applied Physics 130, 180401 (2021). http://doi.org/10.1063/5.0075774
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
DOI: 10.1063/5.0075774
|
|
|
“Effect of electric field and vertical strain on the electro-optical properties of the MoSi2N4 bilayer : a first-principles calculation”. Bafekry A, Stampfl C, Naseri M, Fadlallah MM, Faraji M, Ghergherehchi M, Gogova D, Feghhi SAH, Journal Of Applied Physics 129, 155103 (2021). http://doi.org/10.1063/5.0044976
Abstract: Recently, a two-dimensional (2D) MoSi 2N 4 (MSN) structure has been successfully synthesized [Hong et al., Science 369(6504), 670-674 (2020)]. Motivated by this result, we investigate the structural, electronic, and optical properties of MSN monolayer (MSN-1L) and bilayer (MSN-2L) under the applied electric field (E-field) and strain using density functional theory calculations. We find that the MSN-2L is a semiconductor with an indirect bandgap of 1.60 (1.80)eV using Perdew-Burke-Ernzerhof (HSE06). The bandgap of MSN-2L decreases as the E-field increases from 0.1 to 0.6V/angstrom and for larger E-field up to 1.0V/angstrom the bilayer becomes metallic. As the vertical strain increases, the bandgap decreases; more interestingly, a semiconductor to a metal phase transition is observed at a strain of 12 %. Furthermore, the optical response of the MSN-2L is in the ultraviolet (UV) region of the electromagnetic spectrum. The absorption edge exhibits a blue shift by applying an E-field or a vertical compressive strain. The obtained interesting properties suggest MSN-2L as a promising material in electro-mechanical and UV opto-mechanical devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
DOI: 10.1063/5.0044976
|
|
|
“Torque field and skyrmion motion by spin transfer torque in a quasi-2D interface in presence of strong spin-orbit interaction”. Osca J, Sorée B, Journal Of Applied Physics 130, 133903 (2021). http://doi.org/10.1063/5.0063887
Abstract: We investigate the torque field and skyrmion motion at an interface between a ferromagnet hosting a skyrmion and a material with a strong spin-orbit interaction. We analyze both semiconductor materials and topological insulators using a Hamiltonian model that includes a linear term. The spin torque-inducing current is considered to flow in the single band limit; therefore, a quantum model of current is used. Skyrmion motion due to spin transfer torque proves to be more difficult in the presence of a spin-orbit interaction in the case where only interface in-plane currents are present. However, edge effects in narrow nanowires can be used to drive the skyrmion motion and to exert a limited control on its motion direction. We also show the differences and similarities between torque fields due to electric current in the many and single band limits. Published under an exclusive license by AIP Publishing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
DOI: 10.1063/5.0063887
|
|
|
“Influence of randomly distributed vacancy defects on thermal transport in two-dimensional group-III nitrides”. Karaaslan Y, Haskins JB, Yapicioglu H, Sevik C, Journal Of Applied Physics 129, 224304 (2021). http://doi.org/10.1063/5.0051975
Abstract: Efficient thermal transport control is a fundamental issue for electronic device applications such as information, communication, and energy storage technologies in modern electronics in order to achieve desired thermal conditions. Structural defects in materials provide a mechanism to adjust the thermal transport properties of these materials on demand. In this context, the effect of structural defects on lattice thermal conductivities of two-dimensional hexagonal binary group-III nitride (XN, X = B, Al, and Ga) semiconductors is systematically investigated by means of classical molecular dynamics simulations performed with recently developed transferable inter-atomic potentials accurately describing defect energies. Here, two different Green-Kubo based approaches and another approach based on non-equilibrium molecular dynamics are compared in order to get an overall understanding. Our investigation clearly shows that defect concentrations of 3% decrease the thermal conductivity of systems containing these nitrites up to 95%. Results hint that structural defects can be used as effective adjustment parameters in controlling thermal transport properties in device applications associated with these materials. Published under an exclusive license by AIP Publishing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
DOI: 10.1063/5.0051975
|
|
|
“Interatomic potential for predicting the thermal conductivity of zirconium trisulfide monolayers with molecular dynamics”. Saiz F, Karaaslan Y, Rurali R, Sevik C, Journal Of Applied Physics 129, 155105 (2021). http://doi.org/10.1063/5.0046823
Abstract: We present here a new interatomic potential parameter set to predict the thermal conductivity of zirconium trisulfide monolayers. The generated Tersoff-type force field is parameterized using data collected with first-principles calculations. We use non-equilibrium molecular dynamics simulations to predict the thermal conductivity. The generated parameters result in very good agreement in structural, mechanical, and dynamical parameters. The room temperature lattice thermal conductivity ( kappa) of the considered crystal is predicted to be kappa x x = 25.69Wm – 1K – 1 and kappa y y = 42.38Wm – 1K – 1, which both agree well with their corresponding first-principles values with a discrepancy of less than 5%. Moreover, the calculated kappa variation with temperature (200 and 400 K) are comparable within the framework of the accuracy of both first-principles and molecular dynamics simulations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
DOI: 10.1063/5.0046823
|
|
|
“Misfit dislocation structure and thermal boundary conductance of GaN/AlN interfaces”. Sun J, Li Y, Karaaslan Y, Sevik C, Chen Y, Journal Of Applied Physics 130, 035301 (2021). http://doi.org/10.1063/5.0049662
Abstract: The structure and thermal boundary conductance of the wurtzite GaN/AlN (0001) interface are investigated using molecular dynamics simulation. Simulation results with three different empirical interatomic potentials have produced similar misfit dislocation networks and dislocation core structures. Specifically, the misfit dislocation network at the GaN/AlN interface is found to consist of pure edge dislocations with a Burgers vector of 1/3(1 (2) over bar 10) and the misfit dislocation core has an eight-atom ring structure. Although different interatomic potentials lead to different dislocation properties and thermal conductance values, all have demonstrated a significant effect of misfit dislocations on the thermal boundary conductance of the GaN/AlN (0001) interface. Published under an exclusive license by AIP Publishing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
DOI: 10.1063/5.0049662
|
|