Spin Hall effect

The Spin Hall Effect (SHE) is a transport phenomenon predicted by Russian physicists M.I. Dyakonov and V.I. Perel in 1971. It consists of the appearance of spin accumulation on the lateral surfaces of an electric current-carrying sample, the signs of the spin directions being opposite on the opposing boundaries. In a cylindrical wire, the current-induced surface spins will wind around the wire. When the current direction is reversed, the directions of spin orientation is also reversed.

The Spin Hall Effect is a transport phenomenon consisting of the appearance of spin accumulation on the lateral surfaces of a sample carrying electric current. The opposing surface boundaries will have spins of opposite sign. It is analogous to the classical Hall effect, where charges of opposite sign appear on the opposing lateral surfaces in an electric-current carrying sample in a magnetic field. In the case of the classical Hall effect the charge build up at the boundaries is in compensation for the Lorentz force acting on the charge carriers in the sample due to the magnetic field. No magnetic field is needed for the SHE which is a purely spin-based phenomenon. The SHE belongs to the same family as the anomalous Hall effect, known for a long time in ferromagnets, which also originates from spin-orbit interaction.

Predicted by Russian physicists M.I. Dyakonov and V.I. Perel in 1971.

The term "Spin Hall Effect" was introduced by Jorge Hirsch in 1999. Unaware of the work of Dyakonov and Perel, Hirsch used subtle physical reasoning based on the anomalous Hall effect to predict both the SHE and the inverse SHE. Averkiev and Dyakonov had earlier predicted the SHE [N.S. Averkiev and M.I. Dyakonov, JETP Lett. 35, 196 (1983)], and it had been observed [A.A. Bakun et al., JETP Lett. 40, 1293 (1984)].

Experimentally, the Spin Hall Effect was observed in semiconductors more than 30 years after the original prediction.

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