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

TL;DR

This study investigates the electronic structure of MgB$_2$ using x-ray emission and absorption spectroscopy, confirming theoretical predictions and highlighting charge transfer effects related to its high superconducting transition temperature.

Contribution

The paper provides experimental x-ray spectra of MgB$_2$ that align with theoretical calculations, offering insights into its electronic structure and charge transfer mechanisms.

Findings

X-ray spectra agree with theoretical calculations

Charge transfer from σ to π bands observed

Charge transfer influences high-Tc superconductivity

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 $\sigma$ to $\pi$ bands, which creates holes at the top of the bonding $\sigma$ bands and drives the high-T$_c$