Non-ballistic spin field-effect transistor

TL;DR

This paper introduces a spin field-effect transistor leveraging combined Rashba and Dresselhaus spin-orbit couplings, enabling spin transport tolerant to scattering and relaxing the need for ballistic conditions.

Contribution

It presents a novel design for a spin transistor that maintains spin coherence despite scattering by tuning spin-orbit interactions to equal strengths.

Findings

Spin transport is tolerant to spin-independent scattering.

Equal Rashba and Dresselhaus interactions produce k-independent eigenspinors.

Implementation with 2D devices and quantum wires is feasible.

Abstract

We propose a spin field-effect transistor based on spin-orbit (s-o) coupling of both the Rashba and the Dresselhaus types. Differently from earlier proposals, spin transport through our device is tolerant against spin-independent scattering processes. Hence the requirement of strictly ballistic transport can be relaxed. This follows from a unique interplay between the Dresselhaus and the (gate-controlled) Rashba interactions; these can be tuned to have equal strengths thus yielding k-independent eigenspinors even in two dimensions. We discuss implementations with two-dimensional devices and quantum wires. In the latter, our setup presents strictly parabolic dispersions which avoids complications arising from anticrossings of different bands.