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The 'Larmor clock' in silicon

March 7, 2011 - 12:30pm
Speaker: 
Ian Applebaum
Institution: 
University of Maryland Physics

To study the possibilities of non-equilibrium spin-polarized electron transport in semiconductors, my group has over the past several years utilized ballistic hot electron techniques for injection and detection in silicon, arguably the "hydrogen atom" of semiconductors from the spin point of view.[1] We have used these all-electrical methods to achieve spin transport over truly macroscopic distances of even several millimeters,[2] and used a "Larmor clock" spin precession technique to recover complete time-of-flight transport distributions even with quasi-static measurements.[3] These results have enabled us to reveal the subtle differences between spin and charge transport characteristics in the same intrinsic bulk material,[4,5] and have recently been used to elucidate the role of interfaces[6] and extrinsic impurity state spectrum[7] on spin relaxation and dephasing[8]. Exciting future research along this direction is suggested for instance by initial results showing that our measurements are potentially capable of resolving subtleties of the spin-dependent bandstructure such as spin “hot-spots”.[9]

  1. [1] Ian Appelbaum, B. Huang, and D.J. Monsma, "Electronic measurement and control of spin transport in silicon", Nature 447, 295 (2007).
  2. [2] B. Huang, H.-J. Jang, and Ian Appelbaum, "Geometric dephasing-limited Hanle effect in long-distance lateral silicon spin transport devices", Appl. Phys. Lett. 93, 162508 (2008).
  3. [3] H.-J. Jang and Ian Appelbaum, "Spin Polarized Electron Transport near the Si/SiO2 Interface", Phys. Rev. Lett. 103, 117202 (2009).
  4. [4] B. Huang and Ian Appelbaum, "Spin Dephasing in Drift-Dominated Semiconductor Spintronics Devices", Phys. Rev. B 77, 165331 (2008).
  5. [5] Ian Appelbaum, "A Haynes-Shockley Experiment for Spin-Polarized Electron Transport in Silicon", Solid-State Electronics 53, 1242 (2009).
  6. [6] B. Huang, D.J. Monsma, and Ian Appelbaum, "Coherent spin transport through a 350-micron-thick Silicon wafer", Phys. Rev. Lett. 99, 177209 (2007).
  7. [7] Yuan Lu, Jing Li, and Ian Appelbaum, "Spin-Polarized Transient Electron Trapping in Si:P", arXiv:condmat/1101.1944 (2011).
  8. [8] Biqin Huang and Ian Appelbaum, "The Larmor clock and anomalous spin dephasing in silicon", Phys. Rev. B Rapid Comm. 82, 241202(R) (2010).
  9. [9] J. Fabian and S. Das Sarma, Phys. Rev. Lett. 81, 5624 (1998).
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