Anisotropic spin relaxation in quantum dots

TL;DR

This paper theoretically investigates how phonon-assisted spin relaxation in elliptical quantum dots depends on magnetic field orientation, revealing anisotropic behavior influenced by spin-orbit interactions and dot geometry.

Contribution

It introduces a method to determine Rashba and Dresselhaus spin-orbit coupling parameters and quantum dot ellipticity from relaxation rate angular dependence.

Findings

Relaxation rate is anisotropic with respect to in-plane magnetic field orientation.

Interference between Rashba and Dresselhaus terms causes angular sensitivity.

Method to extract spin-orbit parameters and dot shape from experimental data.

Abstract

We study theoretically phonon-assisted spin relaxation of an electron confined in an elliptical quantum dot (QD) subjected to a tilted magnetic field. In the presence of both Rashba and Dresselhaus spin-orbit terms, the relaxation rate is anisotropic with respect to the in-plane field orientation. This anisotropy originates from the interference, at nonzero tilt angle, between the two spin-orbit terms. We show that, in a narrow range of magnetic field orientations, the relaxation rate exhibits anomalous sensitivity to variations of the QD parameters. In this range, the relative change in the relaxation rate with in-plane field orientation is determined {\em solely} by the spin-orbit coupling strengths and by the dot geometry. This allows simultaneous determination of both Rashba and Dresselhaus coupling parameters and the dot ellipticity from analysis of the angular dependence of the relaxation rate.