Manipulating Spin Coherence in Solid State Systems
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Date: 11-09-2005
Start Time:
4:00pm
End Time: 5:00pm
Speaker: Sayantani Ghosh
From:
University of California, Santa Barbara
Location: Interschool Lab, 7th floor, Schapiro/CEPSR
Hosted by:
Center for Integrated Science
Abstract:
Control over spins in the solid state forms the basis for spintronics and quantum information technologies. Here, I provide an overview of the study of coherent spin dynamics in two very different systems, an insulating quantum magnet and a nonmagnetic semiconductor, including a discussion of temporally-resolved magnetic and optical measurements. I will discuss the dynamic properties of the low temperature spin liquid phase observed in a dilute magnetic compound Li(Ho,Y)F [1,2]. Here we show that the excitation spectrum consists of collections of discrete, fluctuating spin clusters with well-defined normal mode frequencies that can be addressed via the technique of spectral “hole burning”. Once set into resonance, these clusters, composed of hundreds of spins, remain coherent for up to tens of seconds. Spin dynamics in semiconductor microcavities is another new and promising research field as it offers unique means of controlling light-matter interactions. I will discuss the photonic manipulation of electron spins in optically-pumped GaAs microcavities [3] and its implications for the underlying physics of quantum information processing in the solid state.
- 1. S. Ghosh, R. Parthasarathy, T.F. Rosenbaum and G. Aeppli, Science 296, 2002,2195-2198
- 2. S. Ghosh, T.F. Rosenbaum, G. Aeppli and S.N. Coppersmith, Nature 425, 2003, 48-51
- 3. S. Ghosh, W.H. Wang, F.M. Mendoza, R. C. Myers, X. Li, N. Samarth, A.C. Gossard, and D.D. Awschalom, submitted, Nature Materials (2005).