Resonant inelastic x-ray scattering spectra of magnesium diboride

Using the tight-binding linear muffin-tin orbital method, the soft x-ray fluorescence K-emission spectra of boron in MgB2, excited close to the absorption edge, are estimated. In the calculations, the angle of incidence theta between the direction of the incoming photon and the hexagonal axis of the specimen is 60degrees and 75degrees. Comparison with experiment is possible in the former case, where good agreement is found. The physically different sheets of the Fermi surface are shown to induce well separated peaks in the resonant inelastic x-ray scattering spectrum. Furthermore, a resonant feature below the Fermi energy is predicted for the larger angle. This feature can be related to the excitations to the antibonding B pi-band in the neighborhood of the L-H line in the Brillouin zone.