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“Wave-packet propagation in a graphene geometric diode”. Andelkovic M, Rakhimov KY, Chaves A, Berdiyorov GR, Milošević, MV, Physica. E: Low-dimensional systems and nanostructures 147, 115607 (2023). http://doi.org/10.1016/J.PHYSE.2022.115607
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.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.3
Times cited: 1
DOI: 10.1016/J.PHYSE.2022.115607
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“Low-dimensional confining structures on the surface of helium films suspended on designed cavities”. Dantas DS, Chaves A, Farias GA, Ramos ACA, Peeters FM, Journal of low temperature physics 173, 207 (2013). http://doi.org/10.1007/s10909-013-0895-5
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.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.3
Times cited: 1
DOI: 10.1007/s10909-013-0895-5
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“Tunable effective masses of magneto-excitons in two-dimensional materials”. Chaves A, Peeters FM, Solid State Communications 334, 114371 (2021). http://doi.org/10.1016/J.SSC.2021.114371
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.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.554
DOI: 10.1016/J.SSC.2021.114371
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“Stable Janus TaSe₂, single-layers via surface functionalization”. Kahraman Z, Baskurt M, Yagmurcukardes M, Chaves A, Sahin H, Applied Surface Science 538, 148064 (2021). http://doi.org/10.1016/J.APSUSC.2020.148064
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.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.387
DOI: 10.1016/J.APSUSC.2020.148064
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“Exotic state seen at high temperatures”. Chaves A, Neilson D, Nature 574, 39 (2019). http://doi.org/10.1038/D41586-019-02906-9
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.
Keywords: Editorial; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 40.137
Times cited: 2
DOI: 10.1038/D41586-019-02906-9
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