The projected density of states for the ground and excited states of B in MgB2 was calculated using the augmented plane wave plus local orbital method. The core-hole interaction was found to have a significant effect upon the B pxpy states, but had little effect upon the more metallic B pz states. The unoccupied B pxpy DOS near to the Fermi level decreased as a function of core-hole strength. Comparisons with experimental electron energy loss spectra of the B K edge showed that a simulation with half a core hole provided the best approximation to the final states in MgB2.

Core-Hole Effects on the B K Edge in MgB2. B.Jiang, N.Jiang, J.C.H.Spence: Journal of Physics - Condensed Matter, 2003, 15, 1299-304

Figure 18

Fermi Surface for MgB2 in the Fifth Band