Quantum tunneling through planar p-n junctions in HgTe quantum wells

TL;DR

This paper investigates electron tunneling in HgTe quantum wells with inverted band structure, revealing tunable conductance and spin effects due to topological states and Rashba spin-orbit interaction.

Contribution

It demonstrates controllable intraband and interband tunneling, conductance plateaus from topological edge states, and spin rotation effects in HgTe quantum well p-n junctions.

Findings

Perfect intraband transmission for electrons perpendicular to the interface

Conductance can be switched via gate voltage through topological edge states

Spin orientation can be rotated by Rashba spin-orbit interaction

Abstract

We demonstrate that a p-n junction created electrically in HgTe quantum wells with inverted band-structure exhibits interesting intraband and interband tunneling processes. We find a perfect intraband transmission for electrons injected perpendicularly to the interface of the p-n junction. The opacity and transparency of electrons through the p-n junction can be tuned by changing the incidence angle, the Fermi energy and the strength of the Rashba spin-orbit interaction. The occurrence of a conductance plateau due to the formation of topological edge states in a quasi-one-dimensional p-n junction can be switched on and off by tuning the gate voltage. The spin orientation can be substantially rotated when the samples exhibit a moderately strong Rashba spin-orbit interaction.