The Spin Hall Effect- Dr Jörg Wunderlich (Hitachi Lab)

We realized an all semiconductor spin Hall effect transistor by combining the Spin transistor concept proposed by Datta and Das with the (inverse) spin Hall effect (iSHE) detection. We first discuss the Spin Hall effect in a device where spins are optically generated in the depletion layer of a reverse biased pn-junction and injected into a 2-dimensional electron gas (2DEG). In the 2DEG, the spin-orbit interaction (SOI) can be modulated with electrostatic gates to control locally the spin-polarziation. This concept of spin-manipulation is tested by using the SHE. The SHE is also used to demonstrate a spin AND logic function in a 2D channel with two gates. Finally, we demonstrate the inverse SHE detection in a semiconductor combined with an electrical spin injection and
manipulation, and to perform a quantitative analysis of the measured iSHE voltages. In our GaAs microchannel with an Fe injection electrode, the spin current in a lateral semiconductor channel is detected by the iSHE and the spin polarization is simultaneously measured by the non-local spin valve effect using an additional Fe electrode. The spins in the channel are manipulated via the Hanle spin precession induced by an applied magnetic eld and via a drift of electrons induced by an applied electrical bias. The output spin signal is suppressed or enhanced depending on the applied drift, rendering the device an electrically controlled spin amplifier.