Spin's Lifetime Extended

摘要

Electrons in semiconductors are subject to forces that make their spins flip. According to new evidence, if an ensemble of spins curls into a helix, the collective spin lifetime can be greatly enhanced.rnOver the past decade, electron spin - the electron's intrinsic rotation, which is commonly described as 'up' and 'down' and which gives rise to its magnetic moment - has come to the forefront of research in solid-state physics. A whole new field, called spintronics, has emerged as an umbrella for both applied and fundamental research on spin transport and spin control in metals and semiconductors. On the applied front, spintronics is already realizing its potential in applications such as magnetic read heads in computers' hard disks or magnetic random-access memories that are non-volatile - that is, they can retain information even when the power is turned off. On the fundamental side, the field is generating equally fascinating discoveries of spin phenomena. One such discovery, the realization of a 'persistent spin helix' in a semiconductor is reported by Koralek and colleagues on page 610 of this issue.