ELECTRON PRECESSION AND COHERENCE IN MAGNETIC QUANTUM STRUCTURES - ROOM-TEMPERATURE SPIN MEMORY

A fundamental understanding of coherent electronic processes in nanome ter-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 relativel y unexplored area is processes involving electronic spin degrees of fr eedom. Femtosecond-resolved optical techniques are used to create a su perposition of the basis spin states defined by an applied field and t o 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 t emperature. (C) 1998 Elsevier Science Ltd. All rights reserved.