Control of Spin Helix Symmetry in Semiconductor Quantum Wells by Crystal Orientation

TL;DR

This paper explores how crystal orientation influences spin-preserving symmetries in zinc-blende semiconductor quantum wells, revealing conditions for conserved spin operators and analyzing higher-order effects on spin dynamics.

Contribution

It demonstrates that conserved spin operators depend on the crystal orientation, specifically requiring at least two Miller indices to match in modulus, and analyzes the resulting spin-orbit fields.

Findings

Conserved spin operators exist only for specific crystal orientations.

The spin-orbit field can have both in-plane and out-of-plane components.

Higher-order Dresselhaus effects influence weak localization corrections.

Abstract

We investigate the possibility of spin-preserving symmetries due to the interplay of Rashba and Dresselhaus spin-orbit coupling in n-doped zinc-blende semiconductor quantum wells of general crystal orientation. It is shown that a conserved spin operator can be realized if and only if at least two growth-direction Miller indices agree in modulus. The according spin-orbit field has in general both in-plane and out-of-plane components and is always perpendicular to the shift vector of the corresponding persistent spin helix. We also analyze higher-order effects arising from the Dresselhaus term, and the impact of our results on weak (anti)localization corrections.