Leakage-induced decoherence during single electron spin manipulation in a double quantum dot

TL;DR

This paper investigates how leakage currents cause decoherence in single electron spin manipulation within double quantum dots, showing that leakage is the main decoherence source, while nuclear fluctuations are negligible.

Contribution

It provides a theoretical analysis identifying leakage current as the primary decoherence mechanism during spin control in double quantum dots.

Findings

Oscillation frequency and relaxation time match experimental data.

Leakage current is the dominant decoherence source.

Nuclear field fluctuations have minimal impact on decoherence.

Abstract

Coherent single electron spin oscillation in a double quantum dot system driven by a magnetic electron spin resonance field is studied theoretically using a Bloch-type rate equation approach. The oscillation frequency and relaxation time obtained using typical model parameters are consistent with experiment findings. The dominant decoherence mechanism is identified to be a leakage current through a Coulomb blockade barrier at a quantum dot during the spin manipulation. Nuclear field fluctuations which induce a long relaxation time are found to contribute only negligibly to the decoherence despite an earlier suggestion.