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Terahertz imaging of Landau levels in HgTe-based topological insulators 
Auteur(s): Kadykov A., Torres Jeremie, Krishtopenko S., Consejo C., Ruffenach S., Marcinkiewicz M., But D., Knap W., Morozov Sergey V., Gavrilenko Vladimir I., Mikhailov Nikolai N., Dvoretsky Sergey A., Teppe F.
(Article) Publié:
Applied Physics Letters, vol. 108 p.262102 (2016)
Ref HAL: hal-01358769_v1
DOI: 10.1063/1.4955018
WoS: WOS:000379178200019
Exporter : BibTex | endNote
11 Citations
Résumé: We report on sub-terahertz photoconductivity under the magnetic field of a two dimensional topologicalinsulator based on HgTe quantum wells. We perform a detailed visualization of Landau levelsby means of photoconductivity measured at different gate voltages. This technique allows oneto determine a critical magnetic field, corresponding to topological phase transition from invertedto normal band structure, even in almost gapless samples. The comparison with realistic calculationsof Landau levels reveals a smaller role of bulk inversion asymmetry in HgTe quantum wellsthan it was assumed previously.
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Non-trivial Berry phase in the Cd3As2 3D Dirac semimetal
Auteur(s): Desrat W., Consejo C., Teppe F., Contreras S., Marcinkiewicz M., Knap W., Nateprov A., Arushanov E.
Conference: EDISON 19 (Salamanca, ES, 2015-06-29)
Texte intégral en Openaccess : 
Ref HAL: hal-01932656_v1
DOI: 10.1088/1742-6596/647/1/012064
WoS: 000366236800064
Exporter : BibTex | endNote
8 Citations
Résumé: We present magnetotransport measurements performed on Cd3As2 samples. Our results confirm the existence of 3D Dirac fermions in this material with a π Berry phase. A metal-insulator transition driven by the magnetic field is also observed for B < 1 T. Finally the in situ rotation of the sample reveals that the Fermi surface is a weakly anisotropic ellipsoid.
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Terahertz studies of 2D and 3D topological transitions
Auteur(s): Marcinkiewicz M., Teppe F., Consejo C., Diakonova N., Desrat W., Coquillat D., Ruffenach S., Knap W., Mikhailov N. N., Dvoretskii S. A., Gonzalez-Posada F., Rodriguez Jean-Baptiste, Tournié E.
Conference: 19TH INTERNATIONAL CONFERENCE ON ELECTRON DYNAMICS IN SEMICONDUCTORS, OPTOELECTRONICS AND NANOSTRUCTURES (EDISON' 19) (Salamanca, ES, 2015)
Texte intégral en Openaccess :
Ref HAL: hal-01249953_v2
DOI: 10.1088/1742-6596/647/1/012037
WoS: WOS:000366236800037
Exporter : BibTex | endNote
1 Citation
Résumé: We report terahertz measurements on bulk HgCdTe crystals at the semiconductor- to-semimetal topological transition and InAs/GaSb inverted band structure quantum well. We show that physical parameters of these narrow gap systems driven in specific topological phases can be efficiently extracted by means of terahertz photoconductivity studies.
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