Spin dynamics of GaAs(100) by two-photon photoemission

Abstract

On p-doped GaAs(100) surface, the band bending arising from Fermi-level pinning significantly affects the carrier and spin dynamics. In this paper, we report th e dynamics of spin polarization of p-doped GaAs(100) by using the time-resolve d and the energy-resolved two-photon photoemission techniques. By measuring the spin and energy relaxation of electrons emitted from the GaAs(100) surfaces, th e dynamics of spin polarization were observed and the mechanism of spin relaxati on was discussed as well. The experimental measurements together with the theore tical results indicate that the Bir-Aronov-Pikus (BAP) mechanism plays a dominan t role for spin polarization decay, especially in band bending region of GaAs(10 0).