Phonon-mediated electron spin phase diffusion in a quantum dot

TL;DR

This paper proposes a phonon-mediated mechanism for electron spin decoherence in quantum dots, emphasizing spin phase diffusion caused by phonon-induced fluctuations in g-factor and hyperfine interactions, with distinct temperature and magnetic field dependencies.

Contribution

It introduces a novel spin relaxation process involving phonon-mediated spin phase diffusion, differing from traditional spin-flip transition models.

Findings

Highly efficient spin relaxation in semiconductor quantum dots.

Distinct temperature and magnetic field dependence compared to spin-flip mechanisms.

Potential for experimental verification of the proposed mechanism.

Abstract

An effective spin relaxation mechanism that leads to electron spin decoherence in a quantum dot is proposed. In contrast to the common calculations of spin-flip transitions between the Kramers doublets, we take into account a process of phonon-mediated fluctuation in the electron spin precession and subsequent spin phase diffusion. Specifically, we consider modulations in the longitudinal g-factor and hyperfine interaction induced by the phonon-assisted transitions between the lowest electronic states. Prominent differences in the temperature and magnetic field dependence between the proposed mechanisms and the spin-flip transitions are expected to facilitate its experimental verification. Numerical estimation demonstrates highly efficient spin relaxation in typical semiconductor quantum dots.