Intrinsic Spin Hall Effect

A brief review is given on the spin Hall effect, where an external electric field induces a transverse spin current. It has been recognized over 30 years that such effect occurs due to impurities in the presence of spin-orbit coupling. Meanwhile, it was proposed recently that there is also an intrinsic contribution for this effect. We explain the mechanism for this intrinsic spin Hall effect. We also discuss recent experimental observations of the spin Hall effect.Comment: 13 pages, 3 figures, to appear in Advances in Solid State Physics, Vol 45(2005), edited by B. Kramer, changes in Sections 3 and 4.

Spin Hall Effect in p-type Semiconductors

The spin Hall effect is a phenomenon of inducing spin current by an external electric field. We recently proposed that this effect can occur in p-type semiconductors without relying upon any disorder scattering [S. Murakami et al., Science 301, 1348 (2003)]. This intrinsic effect is due to the ``Berry phase in momentum space'', representing topological structure of the Bloch band structure. We explain how the Berry phase brings about the spin Hall effect, and review several interesting aspects of this effectComment: 6 pages, 1 figure, prepared for Proceedings of International Symposium on Mesoscopic Superconductivity and Spintronics 2004 (Atsugi, Japan, March 1-4, 2004

Theoretical prediction of rotating magnon wavepacket in ferromagnets

We theoretically show that the magnon wavepacket has a rotational motion in two ways; a self-rotation and a motion along the boundary of the sample (edge current). They are similar to cyclotron motion of electrons, but unlike electrons the magnons have no charge and the rotation is not due to Lorenz force. These rotational motions are caused by the Berry phase in momentum space from magnon band structure. Furthermore, these rotational motions of the magnon give an additional correction term to the magnon Hall effect. We also discuss the Berry curvature effect in the classical limit of long-wavelength magnetostatic spin waves having macroscopic coherence length.Comment: 4pages, 2figures, accepted for publication in Phys. Rev. Let