Spin–flip manipulation in HgTe/CdTe heterostructure interface states with Rashba and Dresselhuas spin–orbit interactions

Abstract

We investigate theoretically the electron transport through (001) HgTe/CdTe quantum well heterostructures with inverted-band in planar geometry, where Dirac-like spin–momentum locked interface states have been predicted to be formed and topologically protected against perturbations preserving time-reversal symmetry. In this work, k.p theory and scattering matrix method are used to characterize the interface states of the (001) HgTe/CdTe heterostructure as well as to understand the influence of external electric fields. We find distinct features of the transmission and conductance by considering both Rashba and Dresselhuas spin–orbit interactions. The efficient spin–flip conversion between spin-up and spin-down channels are found by tuning the strength of Rashba and Dresselhuas spin–orbit interactions. It is shown that ideal spin–flip efficiency, i.e., the complete spin–flip, can be achieved with specific spin–orbit coupling strengths. This spin–flip mechanism provides us a realistic way to manipulate the spin orientation which can be constructed low-power information processing device. Furthermore, we address the topological edge states induced unique spin manipulation capability by comparing with the conventional electron transport properties in bulk states. In addition, we analyze the transport behavior when the system in the presence of Zeeman term which may play an important role for a high magnetic field in a realistic experimental setup.