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Title: Suppression of bulk conductivity in InAs/GaSb broken gap composite quantum wells

The two-dimensional topological insulator state in InAs/GaSb quantum wells manifests itself by topologically protected helical edge channel transport relying on an insulating bulk. This work investigates a way of suppressing bulk conductivity by using gallium source materials of different degrees of impurity concentrations. While highest-purity gallium is accompanied by clear conduction through the sample bulk, intentional impurity incorporation leads to a bulk resistance over 1 MΩ, independent of applied magnetic fields. In addition, ultra high electron mobilities for GaAs/AlGaAs structures fabricated in a molecular beam epitaxy system used for the growth of Sb-based samples are reported.
Authors:
; ; ; ; ; ; ; ;  [1]
  1. Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich (Switzerland)
Publication Date:
OSTI Identifier:
22218052
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 11; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ALUMINIUM ARSENIDES; ELECTRIC CONDUCTIVITY; ELECTRON MOBILITY; GALLIUM; GALLIUM ANTIMONIDES; GALLIUM ARSENIDES; IMPURITIES; INDIUM ARSENIDES; LAYERS; MAGNETIC FIELDS; MOLECULAR BEAM EPITAXY; QUANTUM WELLS; TOPOLOGY