English

Phonon-induced decay of the electron spin in quantum dots

Mesoscale and Nanoscale Physics 2016-08-31 v1

Abstract

We study spin relaxation and decoherence in a GaAs quantum dot due to spin-orbit interaction. We derive an effective Hamiltonian which couples the electron spin to phonons or any other fluctuation of the dot potential. We show that the spin decoherence time T2T_2 is as large as the spin relaxation time T1T_1, under realistic conditions. For the Dresselhaus and Rashba spin-orbit couplings, we find that, in leading order, the effective magnetic field can have only fluctuations transverse to the applied magnetic field. As a result, T2=2T1T_2=2T_1 for arbitrarily large Zeeman splittings, in contrast to the naively expected case T2T1T_2\ll T_1. We show that the spin decay is drastically suppressed for certain magnetic field directions and values of the Rashba coupling constant. Finally, for the spin coupling to acoustic phonons, we show that T2=2T1T_2=2T_1 for all spin-orbit mechanisms in leading order in the electron-phonon interaction.

Keywords

Cite

@article{arxiv.cond-mat/0310655,
  title  = {Phonon-induced decay of the electron spin in quantum dots},
  author = {Vitaly N. Golovach and Alexander Khaetskii and Daniel Loss},
  journal= {arXiv preprint arXiv:cond-mat/0310655},
  year   = {2016}
}

Comments

5 pages, 1 figure