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

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 (RSOI). The occurrence of a conductance plateau due to the formation of topological edge states in a quasi-one-dimensional (Q1D) 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 RSOI.