Friday, November 14, 2014

Quantum oscillations of photocurrents in HgTe quantum wells with Dirac and parabolic dispersions



  • 1Terahertz Center, University of Regensburg, 93040 Regensburg, Germany
  • 2Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
  • 3A.V. Rzhanov Institute of Semiconductor Physics, Novosibirsk 630090, Russia
  • 4Novosibirsk State University, Novosibirsk 630090, Russia
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.205415

We report on the observation of magneto-oscillations of terahertz radiation induced photocurrent in HgTe/HgCdTe quantum wells of different widths, which are characterized by a Dirac-like, inverted, and normal parabolic band structure. The photocurrent data are accompanied by measurements of photoresistance (photoconductivity), radiation transmission, as well as magnetotransport. We develop a microscopic model of a cyclotron-resonance assisted photogalvanic effect, which describes main experimental findings. We demonstrate that the quantum oscillations of the photocurrent are caused by the crossing of Fermi level by Landau levels resulting in the oscillations of spin polarization and electron mobilities in spin subbands. Theory explains a photocurrent direction reversal with the variation of magnetic field observed in experiment. We describe the photoconductivity oscillations related with the thermal suppression of the Shubnikov–de Haas effect.
DOI: http://dx.doi.org/10.1103/PhysRevB.90.205415
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  • Published 14 November 2014
  • Received 4 July 2014
  • Revised 29 August 2014
©2014 American Physical Society

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