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Nanoélectronique et Métrologie
Nanoélectronique et Métrologie
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Dernières publications
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Terahertz Spectroscopy of Two-Dimensional Semimetal in Three-Layer InAs/GaSb/InAs Quantum Well 
Auteur(s): Krishtopenko S., Ruffenach S., Gonzalez-posada F., Consejo C., Desrat W., Jouault B., Knap W., Fadeev M. a., Kadykov A., Rumyantsev V. V., Morozov S. V., Boissier G., Tournie E., Gavrilenko V. I., Teppe F.
(Article) Publié:
Jetp Letters / Sov Phys Jetp Lett, vol. 109 p.96-101 (2019)
Ref HAL: hal-02157723_v1
DOI: 10.1134/S0021364019020085
Exporter : BibTex | endNote
Résumé: The features of terahertz photoluminescence and magnetoabsorption in magnetic fields up to 16 T in threelayer InAs/GaSb/InAs quantum wells with a band structure corresponding to a “two-dimensional semimetal” are studied. The comparison of the positions and amplitudes of the photoluminescence lines with the theoretical calculations of oscillator strengths for interband and intraband transitions performed using the eight-band Kane Hamiltonian indicates the existence of a nonradiative recombination channel associated with the overlap of the conduction and valence bands. The energies of interband and intraband Landau level transitions observed in the magnetoabsorption spectra are in good agreement with theoretical calculations, which confirms the predicted band structure.
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Massless Dirac fermions in III-V semiconductor quantum wells
Auteur(s): Krishtopenko S., Desrat W., Spirin K., Consejo C., Ruffenach S., Gonzalez-Posada F., Jouault B., Knap W., Maremyanin K., Gavrilenko V., Boissier G., Torres J., Zaknoune M., Tournié E., Teppe F.
(Article) Publié:
Physical Review B, vol. 99 p.121405 (2019)
Texte intégral en Openaccess : 
Ref HAL: hal-02072785_v1
DOI: 10.1103/PhysRevB.99.121405
Exporter : BibTex | endNote
Résumé: We report on the clear evidence of massless Dirac fermions in two-dimensional system based on III-V semiconductors. Using a gated Hall bar made on a three-layer InAs/GaSb/InAs quantum well, we restore the Landau level fan chart by magnetotransport and unequivocally demonstrate a gapless state in our sample. Measurements of cyclotron resonance at different electron concentrations directly indicate a linear band crossing at the point of the Brillouin zone. Analysis of experimental data within an analytical Dirac-like Hamiltonian allows us not only to determine the velocity (v F = 1.8 × 10 5 m/s) of massless Dirac fermions, but also to demonstrate a significant nonlinear dispersion at high energies.
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Experimental Observation of Temperature-Driven Topological Phase Transition in HgTe/CdHgTe Quantum Wells
Auteur(s): Zholudev M., Kadykov A., Fadeev Mikhail, Marcinkiewicz M., Ruffenach S., Consejo C., Knap W., Torres Jérémie, Morozov Sergey, Gavrilenko Vladimir, Mikhailov Nikolay, Dvoretskii Sergey, Teppe F.
(Article) Publié:
Condensed Matter, vol. 4 p.27 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02072773_v1
DOI: 10.3390/condmat4010027
Exporter : BibTex | endNote
Résumé: We report on the comparison between temperature-dependent magneto-absorption and magnetotransport spectroscopy of HgTe/CdHgTe quantum wells in terms of the detection of the phase transition between the topological insulator and band insulator states. Our results demonstrate that temperature-dependent magnetospectroscopy is a powerful tool to discriminate trivial and topological insulator phases, yet the magnetotransport method is shown to have advantages for the clear manifestation of the phase transition with accurate quantitative values of the transition parameter (i.e., critical magnetic field B c).
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