Electronic structure of MgB$_2$: X-ray emission and absorption studies

Abstract

Measurements of x-ray emission and absorption spectra of the constituents of MgB$_2$ are presented. The results obtained are in good agreement with calculated x-ray spectra, with dipole matrix elements taken into account. The comparison of x-ray emission spectra of graphite, AlB$_2$, and MgB$_2$ in the binding energy scale supports the idea of charge transfer from $σ$ to $π$ bands, which creates holes at the top of the bonding $σ$ bands and drives the high-T$_c$

final version as published in PRB