Spin precession in inversion-asymmetric two-dimensional systems

TL;DR

This paper develops a theoretical method to analyze spin precession in 2D inversion-asymmetric systems with Rashba and Dresselhaus effects, providing insights into spin behavior in spintronic devices like the Datta-Das spin-FET.

Contribution

It introduces an analytical approach to calculate spin expectation values considering both Rashba and Dresselhaus couplings in 2D systems, enhancing understanding of spin dynamics.

Findings

Analytical expressions for spin precession in 2D systems with Rashba and Dresselhaus effects.

Influence of Dresselhaus coupling on spin precession in spin-FETs.

Optimal channel direction identified as [110] for spin control.

Abstract

We present a theoretical method to calculate the expectation value of spin in an inversion-asymmetric two-dimensional (2D) system with respect to an arbitrarily spin-polarized electron state, injected via an ideal point contact. The 2D system is confined in a [001]-grown quantum well, where both the Rashba and the Dresselhaus spin-orbit couplings are taken into account. The obtained analytical results allow more concrete description of the spatial behaviors of the spin precession caused by individually the Rashba and the Dresselhaus terms. Applying the calculation on the Datta-Das spin-FET, whose original design considers only the Rashba effect inside the channel, we investigate the possible influence due to the Dresselhaus spin-orbit coupling. Concluded solution is the choice of +-[1+-10], in particular [110], as the channel direction.