Enhanced spin coherence via mesoscopic confinement during acoustically induced transport

Long coherence lifetimes of electron spins transported using moving potential dots are shown to result from the mesoscopic confinement of the spin vector. The confinement condition to control electron spin dephasing is governed by the relation between the characteristic spin-orbit length of the electron spins and the dimensions of the dot potential, which governs the electron spin coherence lifetime. The spin-orbit length is a sample-dependent parameter determined by the Dresselhaus contribution to the spin-orbit coupling and can be predictably controlled by varying the sample geometry. We further show that the coherence lifetime of the electron spins is independent of the local carrier densities within each potential dot, which suggests the possibility of coherent, long-range transport of single electron spins.