Thermoelectric transport in two-dimensional topological insulator state based on HgTe quantum well

G. M. Gusev, O. E. Raichev, E. B. Olshanetsky, A. D. Levin, Z. D. Kvon, N. N. Mikhailov, S. A. Dvoretsky

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The thermoelectric response of HgTe quantum wells in the state of two-dimensional topological insulator (2D TI) has been studied experimentally. Ambipolar thermopower, typical for an electron-hole system, has been observed across the charge neutrality point, where the carrier type changes from electrons to holes according to the resistance measurements. The hole-type thermopower is much stronger than the electron-type one. The thermopower linearly increases with temperature. We present a theoretical model which accounts for both the edge and bulk contributions to the electrical conductivity and thermoelectric effect in a 2D TI, including the effects of edge to bulk leakage. The model, contrary to previous theoretical studies, demonstrates that the 2D TI is not expected to show anomalies of thermopower near the band conductivity threshold, which is consistent with our experimental results. Based on the experimental data and theoretical analysis, we conclude that the observed thermopower is mostly of the bulk origin, while the resistance is determined by both the edge and bulk transport.

Original languageEnglish
Article number014001
Number of pages11
Journal2D Materials
Volume6
Issue number1
DOIs
Publication statusPublished - 1 Jan 2019

Keywords

  • edge states
  • HgTe quantum well
  • quantum transport
  • thermopower
  • topological insulator

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