Mapping spin-orbit splitting in strained InGaAs epilayers

Time- and spatially-resolved Faraday rotation spectroscopy is used to measure the magnitude and direction of the momentum-dependent spin splitting in strained InGaAs epilayers. The epilayers are lattice-matched to the GaAs substrate and designed to reduce inhomogeneous effects related to strain relaxation. Measurements of momentum-dependent spin splitting as a function of electron spin drift velocity along [100], [010], [110] and [1$\bar{1}$0] directions enable separation of isotropic and anisotropic effective magnetic fields that arise from uniaxial and biaxial strain along $⟨$110$⟩$. We relate our findings to previous measurements and theoretical predictions of spin splitting for inversion symmetry breaking in bulk strained semiconductors.