Electrical manipulation of spins in the Rashba two dimensional electron gas systems

We present our theoretical and experimental studies on manipulation of electron spins based on the Rashba spin-orbit interaction (SOI) in semiconductor heterostructures. Quantum well (QW) thickness dependence of the Rashba SOI strength α is investigated in InP/InGaAs/InAlAs asymmetric QWs by analyzing weak antilocalization. Two different QW thicknesses show inverse N_s dependence of α in the same heterostructures. This inverse N_s dependence of α is explained by the kp perturbation theory. We confirm that narrow wires are effective to suppress the spin relaxation. Spin interference effects due to spin precession are experimentally studied in small array of mesoscopic InGaAs rings. This is an experimental demonstration of a time reversal Aharonov-Casher effect, which shows that the spin precession angle in an InGaAs channel can be controlled by an electrostatic gate.