TY - JOUR
T1 - Unexpected edge conduction in mercury telluride quantum wells under broken time-reversal symmetry
AU - Ma, Eric Yue
AU - Calvo, M. Reyes
AU - Wang, Jing
AU - Lian, Biao
AU - Mühlbauer, Mathias
AU - Brüne, Christoph
AU - Cui, Yong Tao
AU - Lai, Keji
AU - Kundhikanjana, Worasom
AU - Yang, Yongliang
AU - Baenninger, Matthias
AU - König, Markus
AU - Ames, Christopher
AU - Buhmann, Hartmut
AU - Leubner, Philipp
AU - Molenkamp, Laurens W.
AU - Zhang, Shou Cheng
AU - Goldhaber-Gordon, David
AU - Kelly, Michael A.
AU - Shen, Zhi Xun
N1 - Publisher Copyright:
© 2015 Macmillan Publishers Limited.
PY - 2015/5/26
Y1 - 2015/5/26
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 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. This indicates physics beyond simple quantum spin Hall model, including material-specific properties and possibly many-body effects.
AB - 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. This indicates physics beyond simple quantum spin Hall model, including material-specific properties and possibly many-body effects.
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U2 - 10.1038/ncomms8252
DO - 10.1038/ncomms8252
M3 - Article
C2 - 26006728
AN - SCOPUS:84930224930
SN - 2041-1723
VL - 6
JO - Nature communications
JF - Nature communications
M1 - 7252
ER -