Accueil >
La Recherche >
Axes & Equipes >
Physique de l’Exciton, du Photon & du Spin >
Services supports >
Nanoélectronique et Métrologie
Nanoélectronique et Métrologie
1 Membres
Dernières publications
|
|
Band splitting in Cd3As2 measured by magnetotransport 
Auteur(s): Desrat W. , Krishtopenko S., Piot B. A., Orlita M., Consejo C., Ruffenach S., Knap W., Nateprov A., Arushanov E., Teppe F.
(Article) Publié:
Physical Review B, vol. 97 p.245203 (2018)
Ref HAL: hal-01827025_v1
DOI: 10.1103/PhysRevB.97.245203
Exporter : BibTex | endNote
Résumé: Magnetotransport measurements have been performed on (112)-oriented bulk Cd3As2 samples with in situ rotation at low temperature. The frequency analysis of the Shubnikov–de Haas oscillations reveals two weakly separated frequencies arising from two Fermi ellipsoids. The angle dependence of these frequencies is fitted by an analytical expression that we derived for any magnetic field orientation. It is based on an 8 × 8 k · p model which includes the spin-orbit coupling, the crystal field splitting due to tetragonal distortion, and the additional band splitting occurring in noncentrosymmetric crystals. This band splitting is evaluated to a finite value of 30 meV, demonstrating the absence of inversion symmetry in our Cd3 As2 crystal.
|
|
|
|
Temperature-Induced Topological Phase Transition in HgTe Quantum Wells
Auteur(s): Kadykov A., Krishtopenko S., Jouault B., Desrat W., Knap W., Ruffenach S., Consejo C., Torres J., Morozov S. V., Mikhailov N. N., Dvoretskii S. A., Teppe F.
(Article) Publié:
Physical Review Letters, vol. 120 p.086401 (2018)
Texte intégral en Openaccess : 
Ref HAL: hal-01740166_v1
Ref Arxiv: 1710.06666
DOI: 10.1103/PhysRevLett.120.086401
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: We report a direct observation of temperature-induced topological phase transition between trivial and topological insulator in HgTe quantum well. By using a gated Hall bar device, we measure and represent Landau levels in fan charts at different temperatures and we follow the temperature evolution of a peculiar pair of "zero-mode" Landau levels, which split from the edge of electron-like and hole-like subbands. Their crossing at critical magnetic field $B_c$ is a characteristic of inverted band structure in the quantum well. By measuring the temperature dependence of $B_c$, we directly extract the critical temperature $T_c$, at which the bulk band-gap vanishes and the topological phase transition occurs. Above this critical temperature, the opening of a trivial gap is clearly observed.
Commentaires: 5 pages + Supplemental Materials; Phys. Rev. Lett. (accepted). Réf Journal: Phys. Rev. Lett. 120, 086401 (2018)
|
