Electron precession and coherence in magnetic quantum structures: Room-temperature spin memory

A fundamental understanding of coherent electronic processes in nanometer-scale geometries will play an important role in the development of future technologies that rely on the quantum mechanical manipulation of confined electronic states in semiconductor structures. A relatively unexplored area is processes involving electronic spin degrees of freedom. Femtosecond-resolved optical techniques are used to create a superposition of the basis spin states defined by an applied field and to follow the coherent evolution of this population of electronic spins as they precess about the applied field. In a variety of magnetically- and electronically-doped quantum structures and thin films, we find surprisingly long lived electronic spin memory that persists to room temperature. (C) 1998 Elsevier Science Ltd. All rights reserved.