STRAIN DEPENDENCE OF SPIN POLARIZATION OF PHOTOELECTRONS FROM A THIN GAAS LAYER

We studied the strain dependence of the spin polarization of photoelectrons from a thin GaAs epilayer which was strained by a lattice mismatched GaPxAs1-x buffer substrate. The polarizations were measured for seven samples with different residual strains between 0.34% and 0.80%. Our result shows the clear dependence of the polarization on the residual strain in this strain region. The maximum polarization attained by each sample increases gradually from 67% up to 87% with an increase of the residual strain which corresponds to that of the band splitting from 22 to 52 meV. A brief discussion about this behavior is given.