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

Abstract

We simulate the control of the spin states in a two-electron double quantum dot when an external detuning potential is used to pass the system through an anticrossing. The hyperfine coupling of the electron spins with the surrounding nuclei causes not only anticrossing of the spin states but also decoherence of the spin states. We calculate numerically the singlet-triplet decoherence for different detuning values and find good agreement with the experimental measurement results for a similar setup. We predict an interference effect due to the coupling of the T0 and T+ states. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.