Electronic Structure of B-2p State in AlB2 Single Crystal: Direct Observation ofpσand pπDensity of States

Jin Nakamura; Masamitsu Watanabe; Tamio Oguchi; Sin-ya Nasubida; Eiki Kabasawa; Nobuyoshi Yamada; Kazuhiko Kuroki; Hisashi Yamazaki; Shik Shin; Yuji Umeda; Shin Minakawa; Noriaki Kimura; Haruyoshi Aoki

doi:10.1143/JPSJ.71.408

paper

Electronic Structure of B-2p State in AlB2 Single Crystal: Direct Observation ofpσand pπDensity of States

arXiv:cond-mat/0112409 · doi:10.1143/JPSJ.71.408

Abstract

X-ray emission (XES) and absorption (XAS) spectra near the B- $K$ edge were measured on single-crystalline AlB $_{2}$ compound which is an isostructural diboride of superconducting MgB $_{2}$ . The partial density of states (PDOS) of B-2 $p σ$ and $p π$ orbitals were derived from the polarization dependence of XES and XAS spectra. There are considerable amounts of PDOS near the Fermi energy in AlB $_{2}$ similarly to that in MgB $_{2}$ , but there are almost no PDOS in $p σ$ orbitals of AlB $_{2}$ near the Fermi energy, i.e., a pseudo-gap in $p σ$ state and a broad metallic state in $p π$ state are observed. The present result indirectly supports scenarios that the $p σ$ holes play an important role in the occurrence of superconductivity in MgB $_{2}$ . The overall features of PDOS were found to be in good agreement with the result of band calculation of AlB $_{2}$ , but a small discrepancy in the Fermi energy is observed, which is attributed to the Al vacancy in the compounds, i.e., the estimated concentration is Al $_{0.93}$ B $_{2}$ .

LaTeX files and 4 eps figures, to be published in J. Phys. Soc. Jpn

References in corpus (13)

Cited by in corpus (1)

Electronic Structure of B-2 $p σ$ and $p π$ States in MgB $_{2}$ , AlB $_{2}$ and ZrB $_{2}$ Single Crystals