Electronic Structure of B-2p State in AlB<FONT SIZE="-1">2</FONT> Single Crystal: Direct Observation of pσ and pπ Density 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

Electronic Structure of B-2p State in AlB₂ Single Crystal: Direct Observation of pσ and pπ Density 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

著者情報

Jin Nakamura
Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofu, Tokyo 182-8585
Masamitsu Watanabe
RIKEN/Spring-8, Kouto 1-1-1, Mikazuki, Sayo, Hyogo 679-5148
Tamio Oguchi
Department of Quantum Matter, ADSM, Hiroshima University, Higashihiroshima, Hiroshima 739-8530
Sin-ya Nasubida
Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofu, Tokyo 182-8585
Eiki Kabasawa
Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofu, Tokyo 182-8585
Nobuyoshi Yamada
Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofu, Tokyo 182-8585
Kazuhiko Kuroki
Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofu, Tokyo 182-8585
Hisashi Yamazaki
Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofu, Tokyo 182-8585
Shik Shin
The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581
Yuji Umeda
Center for Low Temperature Science, Tohoku University, Sendai 980-8578
Shin Minakawa
Center for Low Temperature Science, Tohoku University, Sendai 980-8578
Noriaki Kimura
Center for Low Temperature Science, Tohoku University, Sendai 980-8578
Haruyoshi Aoki
Center for Low Temperature Science, Tohoku University, Sendai 980-8578

キーワード: MgB₂, AlB₂, single crystal, partial density of state, pσ and pπ orbitals, X-ray emission and absorption spectroscopy

ジャーナル認証あり

2002 年 71 巻 2 号 p. 408-410

DOI https://doi.org/10.1143/jpsj.71.408

詳細

抄録

X-ray emission (XES) and absorption (XAS) spectra near the B-K edge were measured on single-crystalline AlB₂ compound which is an isostructural diboride of superconducting MgB₂. The partial density of states (PDOS) of B-2pσ and pπ orbitals were derived from the polarization dependence of XES and XAS spectra. There are considerable amounts of PDOS near the Fermi energy in AlB₂ similarly to that in MgB₂, but there are almost no PDOS in pσ orbitals of AlB₂ near the Fermi energy, i.e., a pseudo-gap in pσ state and a broad metallic state in pπ state are observed. The present result indirectly supports scenarios that the pσ holes play an important role in the occurrence of superconductivity in MgB₂. The overall features of PDOS were found to be in good agreement with the result of band calculation of AlB₂, 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_0.93B₂.

責任著者(Corresponding author)

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