Contents

10 December 2004
Vol 306, Issue 5703

About The Cover

Cover image expansion

COVER An optical reflectivity image of a semiconductor wire (lower layer) and a digitally filtered image of the spin polarization (upper layer) in three different perspectives. When an electrical current passes through a nonmagnetic semiconductor, the spin Hall effect gives rise to a spin current-a combination of currents of spin-up electrons (red hill) and spin-down electrons (blue valley) in opposite directions-without application of a magnetic field. See page 1910. [Image: Y. K. Kato and D. D. Awschalom]