Polarization-dependent resonant inelastic x-ray scattering of β-Ga2O3: An experimental and computational study

The bulk electronic structure of β-Ga2O3 single crystals was investigated using oxygen K-edge x-ray emission and absorption spectroscopy as well as resonant inelastic soft x-ray scattering. Spectra were obtained for different orientations of the crystal planes with respect to the polarization vector of the incident x-ray beam. The spectra are analyzed with calculations based on density functional theory and using the Bethe–Salpeter equation in the ocean code to take the core–hole interaction into account. These calculations correctly capture all the main features in the experimental spectra, demonstrating the potential of the approach to predict the electronic properties of similar compounds. We find a pronounced anisotropy as a function of the excitation polarization vector and significant differences in the spectral contributions from the inequivalent oxygen atoms of β-Ga2O3.