TY  - JOUR
A1  - Ma, Eric Yue
A1  - Calvo, M. Reyes
A1  - Wang, Jing
A1  - Lian, Biao
A1  - Mühlbauer, Mathias
A1  - Brüne, Christoph
A1  - Cui, Yong-Tao
A1  - Lai, Keji
A1  - Kundhikanjana, Worasom
A1  - Yang, Yongliang
A1  - Baenninger, Matthias
A1  - König, Markus
A1  - Ames, Christopher
A1  - Buhmann, Hartmut
A1  - Leubner, Philipp
A1  - Molenkamp, Laurens W.
A1  - Zhang, Shou-Cheng
A1  - Goldhaber-Gordon, David
A1  - Kelly, Michael A.
A1  - Shen, Zhi-Xun
T1  - Unexpected edge conduction in mercury telluride quantum wells under broken time-reversal symmetry
JF  - Nature Communications
N2  - 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 noninverted 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. This indicates physics beyond simple quantum spin Hall model, including material-specific properties and possibly many-body effects.
KW  - topological insulators
KW  - surface states
KW  - HgTe
KW  - Hg1-xCdxTe
KW  - vacancies
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143185
VL  - 6
IS  - 7252
ER  -