Spin precession due to spin-orbit coupling in a two-dimensional electron gas with spin injection via ideal quantum point contact

TL;DR

This paper analytically investigates spin precession in a 2D electron gas with spin injection, considering Rashba and Dresselhaus spin-orbit couplings, revealing direction-dependent behaviors relevant for spintronic applications.

Contribution

It provides an analytical expression for spin expectation values including both Rashba and Dresselhaus effects in a 2DEG with ideal quantum point contact.

Findings

Rashba-induced spin precession acts like a windshield wiper.

Dresselhaus precession depends on crystallographic direction.

Certain directions exhibit controllable spin precession behaviors.

Abstract

We present the analytical result of the expectation value of spin resulting from an injected spin polarized electron into a semi-infinitely extended 2DEG plane with [001] growth geometry via ideal quantum point contact. Both the Rashba and Dresselhaus spin-orbit couplings are taken into account. A pictorial interpretation of the spin precession along certain transport directions is given. The spin precession due to the Rashba term is found to be especially interesting since it behaves simply like a windshield wiper which is very different from the ordinary precession while that due to the Dresselhaus term is shown to be crystallographic-direction-dependent. Some crystallographic directions with interesting and handleable behavior of spin precession are found and may imply certain applicability in spintronic devices.