Images of edge current in InAs/GaSb quantum wells

Eric M Spanton; Katja C Nowack; Lingjie Du; Gerard Sullivan; Rui-Rui Du; Kathryn A Moler

doi:10.1103/PhysRevLett.113.026804

Images of edge current in InAs/GaSb quantum wells

Phys Rev Lett. 2014 Jul 11;113(2):026804. doi: 10.1103/PhysRevLett.113.026804. Epub 2014 Jul 11.

Authors

Eric M Spanton¹, Katja C Nowack², Lingjie Du³, Gerard Sullivan⁴, Rui-Rui Du³, Kathryn A Moler⁵

Affiliations

¹ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA and Department of Physics, Stanford University, Stanford, California 94305, USA.
² Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA and Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
³ Department of Physics and Astronomy, Rice University, Houston, Texas 77251-1892, USA.
⁴ Teledyne Scientific and Imaging, Thousand Oaks, California 91630, USA.
⁵ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA and Department of Physics, Stanford University, Stanford, California 94305, USA and Department of Applied Physics, Stanford University, Stanford, California 94305, USA.

PMID: 25062220
DOI: 10.1103/PhysRevLett.113.026804

Abstract

Quantum spin Hall devices with edges much longer than several microns do not display ballistic transport; that is, their measured conductances are much less than e(2)/h per edge. We imaged edge currents in InAs/GaSb quantum wells with long edges and determined an effective edge resistance. Surprisingly, although the effective edge resistance is much greater than h/e(2), it is independent of temperature up to 30 K within experimental resolution. Known candidate scattering mechanisms do not explain our observation of an effective edge resistance that is large yet temperature independent.