Thermally robust electrically reversible spin selection in a quantum dot qubit with double reservoir spin accumulations

Spin selection is explored for a quantum dot spin qubit with spin accumulations O mu S and O mu D in the source and drain reservoir, created by ferromagnetic contacts. If O mu S and O mu D have opposite signs, a single electron can be trapped on the quantum dot in two opposite spin states, depending on the source- drain voltage. The selected spin is then electrically reversible and with low error rates for temperatures up to above 4 K. If O mu S and O mu D have the same sign, the spin selectivity is enhanced and persists up to even higher temperature than for a spin qubit with spin accumulation in only one of the reservoirs. These results offer opportunities to improve and electrically control spin qubit initialization and readout at elevated temperature.