Spin-dependent luminescence enhanced by interface stress between III-V alloy layers on excitation of circularly polarized light

The relation between the luminescence polarization for circularly polarized light and the band structure of zincblende semiconductor under two-dimensional stress is theoretically discussed. Two type of samples with an unstrained InP layer and a strained InP layer due to the lattice mismatch are prepared. The luminescence from the InP layer excited by circularly polarized light is analyzed using a Babinet-Soleil compensator, (or phase-modulator) and polarizer. The large luminescence polarization of circularly polarized light is observed in the strained sample. At temperatures below 60 K, the luminescence polarization exceeds 25% which is the maximum value predicted in the unstrained crystal. The experimental results show that the luminescence polarization is increased by the internal strain due to the lattice mismatch.