Abstract
We present an experimental study of low temperature electronic transport in the hybridization gap of inverted composite quantum wells. An 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 in spite of sizable bulk conduction and show only a weak magnetic field dependence—a direct consequence of a gap opening away from the zone center.
- Received 29 April 2011
DOI:https://doi.org/10.1103/PhysRevLett.107.136603
© 2011 American Physical Society