Spin relaxation and decoherence of holes in quantum dots

TL;DR

This paper studies how heavy-hole spins in quantum dots relax and lose coherence under magnetic fields, revealing that decoherence times can surpass relaxation times and depend on spin-orbit interactions and material properties.

Contribution

It provides new insights into heavy-hole spin dynamics, showing potential for longer coherence times than previously known, especially in strongly two-dimensional quantum dots.

Findings

Decoherence time is twice the relaxation time at low temperatures.

Heavy-hole relaxation times can exceed electron relaxation times in certain quantum dots.

Magnetic-field dependence varies with Rashba or Dresselhaus spin-orbit coupling and material g-factors.

Abstract

We investigate heavy-hole spin relaxation and decoherence in quantum dots in perpendicular magnetic fields. We show that at low temperatures the spin decoherence time is two times longer than the spin relaxation time. We find that the spin relaxation time for heavy holes can be comparable to or even longer than that for electrons in strongly two-dimensional quantum dots. We discuss the difference in the magnetic-field dependence of the spin relaxation rate due to Rashba or Dresselhaus spin-orbit coupling for systems with positive (i.e., GaAs quantum dots) or negative (i.e., InAs quantum dots) $g$-factor.