The CEM will be hosting a spring colloquium on Wednesday, March 31, 2010 from 2:00-3:00 p.m. in Smith Seminar Room, Physics Research Building.
Stephen Lyon of Princeton University will be presenting, “Electron Spin Coherence: The Long and Short of It”.
Abstract: Over the last few years there has been a great deal of interest in the possibility of constructing a quantum computer with significant capabilities. However, this requires assembling a large array of two-level systems, qubits, with exceptionally long coherence, while retaining the capability of selectively turning on interactions between pairs of them. Electron spins in semiconductors are attractive candidate qubits since they can be moved and controlled with gates as in classical semiconductor devices. However, the limits to the spin coherence in semiconductors have not been studied since the early days of electron paramagnetic resonance spectroscopy. I will discuss recent pulsed spin resonance measurements of the spin coherence of electrons in isotopically enriched Si. When the electrons are tightly bound, as for a neutral donor, we see exceptionally long spin coherence – orders of magnitude longer than previous results. However, when the electrons are more weakly bound, and near an interface, their coherence time is significantly reduced. The origin of this decoherence is not yet fully understood.
Biographical Sketch: Steve Lyon was an Engineering Physics undergraduate at Cornell, received his Ph.D. in Applied Physics from Caltech, and then joined the faculty in Electrical Engineering at Princeton. He has been a visiting professor at the University of Innsbruck, the University of Oxford, and the University of Linz. His research has concentrated primarily on various aspects of semiconductor and device physics, including studying defects at the silicon/silicon dioxide interface, measuring hot carrier relaxation in III-V semiconductors with CW and ultrafast optical probes, and investigating the mid-infrared properties of quantum wells and self-assembled quantum dots. For the last few years he has been studying the application of electron spins for quantum information.