The Gate-Controlled Spin Transport of Electrons in a Quantum Wire: Effects of Different Geometry of Gates

Abstract

The spin transport properties of electrons through a quasi-one-dimensional quantum wire are investigated. Different numbers of gates which induce the local Rashba-type spin–orbit interaction is considered. The total length of the gate-voltage applied domain is the same in each case, but it is divided into either two or three sections. The ballistic transmission probability as a function of the incident electron energy and the strength of the Rashba spin–orbit interaction is calculated by using the quantum transmitting boundary method. In the double gate geometry, the effect of interactions between neighboring gates is studied. The results show a peculiar change in the transmission probability as a function of the incident electron's energy. The spin-up and spin-down transmission probabilities oscillate alternately as a function of the strength of the Rashba spin–orbit interaction. While the period of oscillation becomes shorter as the strength of the Rashba spin–orbit interaction increases in a single gate system, the period of oscillation is not affected much by the strength of the Rashba spin–orbit interaction in the double or triple gate system. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim