Anisotropy of spin coherence in high mobility quantum wells with arbitrary magnetic fields

TL;DR

This paper provides a theoretical analysis of how spin relaxation and decoherence vary with magnetic field orientation in high mobility quantum wells, highlighting the significant role of cubic spin-orbit terms.

Contribution

It introduces a comprehensive model accounting for arbitrary magnetic fields and cubic spin-orbit interactions, explaining previously unexplained experimental anisotropy observations.

Findings

Relaxation anisotropy depends on magnetic field orientation.

Cubic-in-momentum terms significantly influence spin decoherence.

Theoretical results align with experimental observations.

Abstract

We present a theoretical study of the anisotropy of the spin relaxation and decoherence in typical quantum wells with an arbitrary magnetic field. In such systems, the orientation of the magnetic field relative to the main crystallographic directions is crucial, owing to the lack of spin-rotation symmetry. For typical high mobility samples, relaxation anisotropies in the motional narrowing limit owing to the interplay of Rashba and Dresselhaus spin orbit coupling are calculated. We also include the effect of the cubic-in-momentum terms. Although commonly ignored in literature, the latter were experimentally evidenced by the observation of strong anisotropy in spin decoherence measurements by different experimental groups and has long remained unexplained.