Anisotropic effects and phonon induced spin relaxation in gate-controlled semiconductor quantum dots

TL;DR

This paper investigates how anisotropic gate potentials influence phonon-induced spin relaxation in III-V semiconductor quantum dots, revealing that anisotropy and spin-orbit interactions can be tuned to control spin relaxation rates.

Contribution

It provides a detailed analysis of anisotropic effects on spin relaxation, highlighting the role of gate potentials and spin-orbit coupling in manipulating relaxation rates in quantum dots.

Findings

Anisotropic gate potentials enhance spin-flip rates.

Gate potentials can manipulate level crossing and degeneracy.

Different spin-orbit couplings dominate in InAs and GaAs QDs.

Abstract

In this paper, a detailed analysis of anisotropic effects on the phonon induced spin relaxation rate in III-V semiconductor quantum dots (QDs) is carried out. We show that the accidental degeneracy due to level crossing between the first and second excited states of opposite electron spin states in both isotropic and anisotropic QDs can be manipulated with the application of externally applied gate potentials. In particular, anisotropic gate potentials enhance the phonon mediated spin-flip rate and reduce the cusp-like structure to lower magnetic fields, in addition to the lower QDs radii in III-V semiconductor QDs. In InAs QDs, only the Rashba spin-orbit coupling contributes to the phonon induced spin relaxation rate. However, for GaAs QDs, the Rashba spin-orbit coupling has a contribution near the accidental degeneracy point and the Dresselhaus spin-orbit coupling has a contribution below and above the accidental degeneracy point in the manipulation of phonon induced spin relaxation rates in QDs.