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arXiv · 1308.3375

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

Christophe Charpentier·Stefan Fält·Christian Reichl·Fabrizio Nichele·Atindra Nath Pal·Patrick Pietsch·Thomas Ihn·Klaus Ensslin·Werner Wegscheider
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Abstract

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 lead to a bulk resistance over 1 MΩ. This resistance was found to be independent of applied magnetic fields. 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.

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Christophe Charpentier, Stefan Fält, Christian Reichl, Fabrizio Nichele, Atindra Nath Pal, Patrick Pietsch, Thomas Ihn, Klaus Ensslin, Werner Wegscheider. 2013-08-16. Suppression of bulk conductivity in InAs/GaSb broken gap composite quantum wells. https://doi.org/10.1063/1.4821037

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