A gap-protected zero-Hall effect state in the quantum limit of the non-symmorphic metal KHgSb

Sihang Liang, Satya Kushwaha, Tong Gao, Max Hirschberger, Jian Li, Zhijun Wang, Karoline Stolze, Brian Skinner, B. A. Bernevig, R. J. Cava, N. P. Ong

Research output: Contribution to journalLetter

2 Scopus citations

Abstract

A recurring theme in topological matter is the protection of unusual electronic states by symmetry, for example, protection of the surface states in Z2 topological insulators by time-reversal symmetry1–3. Recently, interest has turned to unusual surface states in the large class of non-symmorphic materials4–12. In particular, KHgSb is predicted to exhibit double quantum spin Hall states10. Here we report measurements of the Hall conductivity in KHgSb in a strong magnetic field B. In the quantum limit, the Hall conductivity is observed to fall exponentially to zero, but the diagonal conductivity is finite. A large gap protects this unusual zero-Hall state. We theoretically propose that, in this quantum limit, the chemical potential drops into the bulk gap, intersecting equal numbers of right- and left-moving quantum spin Hall surface modes to produce the zero-Hall state. The zero-Hall state illustrates how topological protection in a non-symmorphic material with glide symmetry may lead to highly unusual transport phenomena.

Original languageEnglish (US)
Pages (from-to)443-447
Number of pages5
JournalNature Materials
Volume18
Issue number5
DOIs
StatePublished - May 1 2019

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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