Spin dynamics at the singlet-triplet crossings in double quantum dot

TL;DR

This paper simulates spin state control in a double quantum dot, analyzing hyperfine-induced decoherence and predicting interference effects, with results aligning well with experimental data.

Contribution

It provides a numerical analysis of singlet-triplet decoherence and predicts interference effects in spin dynamics under detuning control.

Findings

Decoherence varies with detuning values.

Numerical results agree with experiments.

Interference effects predicted between T0 and T+ states.

Abstract

We simulate the control of the spin states in a two-electron double quantum dot when an external detuning potential is used for passing the system through an anticrossing. The hyperfine coupling of the electron spins with the surrounding nuclei causes the anticrossing of the spin states but also the decoherence of the spin states. We calculate numerically the singlet-triplet decoherence for different detuning values and find a good agreement with experimental measurement results of the same setup. We predict an interference effect due to the coupling of T0 and T+ states.