Many-body theory of phonon-induced spin relaxation and decoherence

TL;DR

This paper introduces a comprehensive theoretical framework for calculating phonon-induced spin relaxation and decoherence, unifying multiple mechanisms and enabling accurate predictions in various materials.

Contribution

It develops a vertex-correction formalism for first-principles calculations of spin dynamics, capturing multiple decoherence mechanisms in a unified way.

Findings

Successfully applied to GaAs, capturing key spin relaxation mechanisms.

Unifies Elliott-Yafet, Dyakonov-Perel, and precession regimes.

Provides a general method for quantitative spin dynamics studies.

Abstract

First-principles calculations enable accurate predictions of electronic interactions and dynamics. However, computing the electron spin dynamics remains challenging. The spin-orbit interaction causes various dynamical phenomena that couple with phonons, such as spin precession and spin-flip e-ph scattering, which are difficult to describe with current first-principles calculations. In this work, we show a rigorous framework to study phonon-induced spin relaxation and decoherence, by computing the spin-spin correlation function and its vertex corrections due to e-ph interactions. We apply this approach to a model system and develop corresponding first-principles calculations of spin relaxation in GaAs. Our vertex-correction formalism is shown to capture the Elliott-Yafet, Dyakonov-Perel, and strong-precession mechanisms - three independent spin decoherence regimes with distinct physical origins - thereby unifying their theoretical treatment and calculation. Our method is general and enables quantitative studies of spin relaxation, decoherence, and transport in a wide range of materials and devices.