Strong charge-transfer effects in the Mg2p−1core-level spectrum ofMgB2

The two available Mg 2p - 1 core-level spectra of the recently discovered high-temperature superconducting MgB 2 crystal exhibit interesting structures, but contradict each other. This motivated us to perform ah initio calculations on the core-level spectra of cluster models. The computed spectra reveal unusual rich and intense structures triggered by a B 2p z →Mg 3s,3p charge transfer.