Spin Relaxation during Electron Transport by SAW

Surface acoustic waves (SAW) have been suggested as a carrier to enable remote transport of a single or multiple electrons from one quantum dot to another while maintaining quantum information encoded in the electron’s spin or orbital degrees of freedom. The pick-up process where electron transport from stationary quantum dot to moving quantum dot defined by the potential minimum of SAW could be highly non-adiabatic, and the electron's orbital wavefunction could end up in a superposition state that includes many highly excited orbital states, gaining energy from the SAW potential. In this work we explore the spin relaxation of an electron in highly excited orbital states through spin-orbit coupling and phonon emission. In particular, we show that electron spin in highly excited orbital states has more relaxation channels and the relaxation rates are much higher than that in the ground state.