Unexpected edge conduction in mercury telluride quantum wells under broken time-reversal symmetry
- Stanford Univ., Stanford, CA (United States)
- Stanford Univ., Stanford, CA (United States); Univ. Wurzburg, Wurzburg (Germany)
- Univ. Wurzburg, Wurzburg (Germany)
- Stanford Univ., Stanford, CA (United States); Univ. of Texas, Austin, TX (United States)
The realization of quantum spin Hall effect in HgTe quantum wells is considered a milestone in the discovery of topological insulators. Quantum spin Hall states are predicted to allow current flow at the edges of an insulating bulk, as demonstrated in various experiments. A key prediction yet to be experimentally verified is the breakdown of the edge conduction under broken time-reversal symmetry. Here we first establish a systematic framework for the magnetic field dependence of electrostatically gated quantum spin Hall devices. We then study edge conduction of an inverted quantum well device under broken time-reversal symmetry using microwave impedance microscopy, and compare our findings to a non-inverted device. At zero magnetic field, only the inverted device shows clear edge conduction in its local conductivity profile, consistent with theory. Surprisingly, the edge conduction persists up to 9 T with little change. Finally, this indicates physics beyond simple quantum spin Hall model, including material-specific properties and possibly many-body effects.
- Research Organization:
- Stanford Univ., CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-76SF00515; PHY-0830228; DMR1305731; FP7-PEOPLE-2010-274769
- OSTI ID:
- 1260964
- Journal Information:
- Nature Communications, Vol. 6; ISSN 2041-1723
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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