Comparison of spin signals in silicon between nonlocal four-terminal and three-terminal methods

The three-terminal (3T) measurement is a method of detecting spin accumulation at a ferromagnetic/semiconductor interface. Spin polarization (P) at the injector with an electric field (P(injector)) and that at the detector without an electric field (P(detector)) were measured separately by using the nonlocal (NL)-Hanle and 3T measurements, and P(injector) and P(detector) exhibited the same behavior with increasing temperature. We also found that the spin lifetime (tau(sp)) in highly doped silicon measured by using the 3T method coincides with that estimated by the NL-Hanle measurement, which shows that the localized state does not exist at the interface. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3536488]