Observation of multichannel quantum coherent transport and electron-electron interaction in Bi2Te3 single crystal

Abstract

The bulk of topological insulators is relatively unexplored, due to the excess contribution of conduction from native defects. Here, we investigate the bulk conduction in a Bi2Te3 crystal having a reduced number of defect states. Our results reveal the presence of three transport regimes which are dominated by thermal activation across the bulk band gap, defect state charge conduction, and quantum coherent transport. The low temperature conductance and magnetoconductance reveal the presence of multichannel two-dimensional quantum coherent transport in the bulk. The number of channels is of the order of quintuple layers, signifying each quintuple layer as a single transport channel. These transport channels exhibit a two-dimensional electron-electron interaction effect causing electron dephasing, whereas the conduction from defect states exhibits a three-dimensional electron-electron interaction effect.