Physical Review Research (Dec 2022)

Large inverted band gap in strained three-layer InAs/GaInSb quantum wells

  • C. Avogadri,
  • S. Gebert,
  • S. S. Krishtopenko,
  • I. Castillo,
  • C. Consejo,
  • S. Ruffenach,
  • C. Roblin,
  • C. Bray,
  • Y. Krupko,
  • S. Juillaguet,
  • S. Contreras,
  • A. Wolf,
  • F. Hartmann,
  • S. Höfling,
  • G. Boissier,
  • J.-B. Rodriguez,
  • S. Nanot,
  • E. Tournié,
  • F. Teppe,
  • B. Jouault

DOI
https://doi.org/10.1103/PhysRevResearch.4.L042042
Journal volume & issue
Vol. 4, no. 4
p. L042042

Abstract

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Quantum spin Hall insulators (QSHIs) based on HgTe and three-layer InAs/GaSb quantum wells (QWs) have comparable bulk band gaps of about 10–18 meV. The former, however, features a band gap vanishing with temperature, while the gap in InAs/GaSb QSHIs is rather temperature independent. Here, we report on the realization of a large inverted band gap in strained three-layer InAs/GaInSb QWs. By temperature-dependent magnetotransport measurements of gated Hall bar devices, we extract a gap as high as 45 meV. By combining local and nonlocal measurements, we detect edge conductivity at temperatures up to 40 K, possibly of topological origin, with equilibrium lengths of a few micrometers. Our results pave the way for the manipulation of topological edge states at high temperatures in QW heterostructures.