Future Trends in Microelectronics: From Nanophotonics to Sensors to Energy

Spin Hall Effect

M. I. Dyakonov

Université Montpellier II, CNRS, 34095 Montpellier, France

1.   Introduction

The spin Hall effect (SHE) originates from the coupling of the charge and spin currents due to spin-orbit interaction. It was predicted in 1971 by Dyakonov and Perel’.^1,2 Following the suggestion in Ref. 3, the first experiments in this domain were done by Fleisher’s group at the Ioffe Institute in St. Petersburg,^4,5 providing the first observation of what is now called the inverse SHE. As for the SHE itself, it had to wait for 33 years before it was experimentally observed by two groups in Santa Barbara⁶ and in Cambridge, UK.⁷ These observations aroused considerable interest and triggered intense research, both experimental and theoretical, with hundreds of publications.

The spin Hall effect consists in spin accumulation at the lateral boundaries of a current-carrying conductor, the directions of the spins being opposite at the opposing boundaries, see Fig. 1. For a cylindrical wire the spins wind around the surface. The boundary spin polarization is proportional to the current and changes sign when the direction of the current is reversed.

The term “spin Hall effect” was introduced by Hirsch in 1998.⁸ It is indeed somewhat similar to the normal Hall effect, where charges of opposite signs accumulate at the sample boundaries due to the action of the Lorentz force in a magnetic field. However, there are significant differences. First, no magnetic field is needed for spin ...