Observation of the spin-Hall effect in Pt/GaAs by circular polarized photoconductivity.

Electrically generated spin accumulation due to the spin Hall effect of Pt/GaAs is detected by circular polarized photoconductivity (CPPC), which shows electron spins with different polarizations accumulated around opposite sample boundaries. An optical absorption model incorporating spin is used to explain these features. The detailed analysis of the observed degree of circular polarization of the photocurrent strongly suggests that Pt and GaAs have the same spin accumulation length in the Pt/GaAs heterostructure.