The intrinsic angular momentum of an electron (spin) – and its associated magnetic moment – can encode information: spin “up” or “down” can be interpreted as “0” or “1”, and potentially be used as the physical realization of a new paradigm of computing beyond electronics. However, this concept of spin-electronics (“spintronics”) needs to be built using a material where the electron spin orientation is preserved over long times (to enable many gate operations) and long distances (so that many devices can be integrated). Silicon, the materials basis for electronics, has been known for decades to have an extraordinarily long spin lifetime, but efforts to achieve even incoherent spin transport in a solid-state device using this material had failed. Using unique spin-polarized hot-electron injection and detection techniques with nano-scale ferromagnetic metal spin “polarizers”, we have observed unprecedented coherence in spin precession measurements, and extracted very long sp in lifetimes of conduction electrons traveling over macroscopic distances, even in the millimeter range. In this talk, I will discuss our recent work in this new field at the intersection of physics and electrical engineering, and prospects for the future of silicon spintronics.
1. Ian Appelbaum, B.Q. Huang, and D.J. Monsma, “Electronic measurement and control of spin transport in silicon,” Nature 447, 295 (2007).
2. B.Q. Huang, D.J. Monsma, and Ian Appelbaum, “Coherent spin transport through a 350-micron-thick silicon wafer,” Phys. Rev. Lett. 99, 177209 (2007).