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Evidence for Helical Edge Modes in Inverted InAs/GaSb Quantum Wells (1105.0137v1)
Published 1 May 2011 in cond-mat.mes-hall
Abstract: We present an experimental study of low temperature electronic transport in the hybridization gap of inverted InAs/GaSb composite quantum wells. Electrostatic gate is used to push the Fermi level into the gap regime, where the conductance as a function of sample length and width is measured. Our analysis shows strong evidence for the existence of helical edge modes proposed by Liu et al [Phys. Rev. Lett., 100, 236601 (2008)]. Edge modes persist inspite of sizable bulk conduction and show only a weak magnetic field dependence - a direct consequence of gap opening away from zone center.