University of Toronto

Title: Spins--Free of Charge

Abstract: The electron has two basic properties that can be used in information technology, charge and spin. The use of charge in the past century gave rise to the field of electronics. In recent years, propelled by possible benefits to quantum information technology, spin has been invoked in what has come to be known as spintronics. One of the main obstacles to the development of spintronics has been the inability to easily inject and control spin currents in semiconductors in the absence of charge currents. Our group is exploring non-linear optical techniques in conjunction with quantum interference processes to overcome this. In particular we have shown how quantum control of the interference between different absorption processes that promote electrons into the conduction band can lead to the production of spin currents with or without charge current in the absence of any external bias. Recent experimental work based on a prototypical semiconductor, GaAs, and continuous or femtosecond laser sources will be described.