X-ray photoemission spectroscopy is used to compare the electronic structures of MgB2 and ZrB2. The B 1s core levels in high-quality MgB2 and ZrB2 exhibit a single asymmetric peak typical of a metallic boride. The Mg 2p core level shows a single peak with negligible intensity in charge-transfer satellites and no correlation effects. The Mg 2p and B 1s core-level spectra exhibit a broad bulk plasmon feature centered at about 22 eV from the main peak, in good accord with calculations. The measured valence bands are consistent with band-structure calculations indicating a higher density of states (DOS) at EF for MgB2 compared to ZrB2. The high Tc in MgB2 is due to p-derived DOS, while ZrB2 is dominated by d-derived states at EF.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Nov 6 2003|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics