Teaching An Old Horse New Tricks: High-Field Magnetic Resonance In Phosphorus- Doped Silicon

Speaker: Prof. Chandrasekhar Ramanathan
Affiliation: Dept. of Chemistry and Physics & Astronomy, Dartmouth



Abstract:  The phosphorus donor impurity in silicon, with its ultra-long coherence time, is a potentially promising candidate for spin-based quantum devices such as quantum information processors, quantum sensors, and as a platform for quantum simulation. While donor impurities in silicon have been studied for over 60 years, new physical phenomena continue to be observed in this system. In this talk I will discuss some recent experiments that have demonstrated that above-band gap optical excitation can result in strong hyperpolarization of the donor nuclear spins. This hyperpolarization has enabled the direct inductive detection of donor nuclear spins at low doping concentrations for the first time. Hyperpolarized nuclear magnetic resonance (NMR) measurements have also observed variations in the donor hyperfine coupling produced by different distributions of silicon isotopes in the vicinity of the donor. Additionally, there are suggestions that it may be possible to enhance donor electron spin coherence times and to change the sign of the induced nuclear spin polarization by changing the wavelength of the optical excitation. The microscopic mechanisms underlying many of these phenomena remain poorly understood.

Biography:  Professor Ramanathan is an experimental physicist working at the interface of quantum information processing and condensed matter physics. He has a B. Tech. degree in Electrical Engineering from the Indian Institute of Technology, Bombay, an M.S. in Biomedical Engineering from the University of North Carolina at Chapel Hill, an S.M. in Technology and Policy and an Sc.D. in Nuclear Engineering from the Massachusetts Institute of Technology. Following postdoctoral training at Harvard Medical School, Nottingham University and MIT, he spent a number of years at MIT as a Research Scientist before joining the faculty of Dartmouth College.

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Date(s) - Oct 23, 2019
1:00 pm - 2:30 pm

Young Hall – #2033
607 Charles E Young Dr E, Los Angeles CA 90095
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