Angle-resolved photoemission study of novel boride compounds

Takashi Takahashi; Seigo Soma; Takafumi Sato

Angle-resolved photoemission study of novel boride compounds

Takashi Takahashi, Seigo Soma, Takafumi Sato

Research output: Contribution to journal › Article › peer-review

Abstract

We have performed high-resolution photoemission spectroscopy on newly discovered novel boride compounds, MgB₂, La-doped CaB₆, and DVB₂C₂. In MgB₂, we observed the superconducting gap of about 4.5 meV with s-wave symmetry. In La-doped CaB ₆, we found a 1 eV energy gap at the X point in the Brillouin zone, in contrast with the LDA band calculation but in good agreement with the GW calculation. This requests reexamination of the excitonic-insulator model based on an overlap of an electron and a hole band at the X point. In DVB ₂C₂, we found two (one electron-like and one hole-like) Fermi surfaces, which are composed of the mixed states of the B2_p, C2_p and Dy5d orbitals, below the antiferro-quadrupolar-ordering temperature.

Original language	English
Pages (from-to)	5-10
Number of pages	6
Journal	journal of the physical society of japan
Volume	71
Issue number	SUPPL.
Publication status	Published - 2002 Dec 1

Keywords

CaBe
DybB
Fermi surface
MgB
Photoemission spectroscopy

ASJC Scopus subject areas

Physics and Astronomy(all)

Cite this

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title = "Angle-resolved photoemission study of novel boride compounds",

abstract = "We have performed high-resolution photoemission spectroscopy on newly discovered novel boride compounds, MgB2, La-doped CaB6, and DVB2C2. In MgB2, we observed the superconducting gap of about 4.5 meV with s-wave symmetry. In La-doped CaB 6, we found a 1 eV energy gap at the X point in the Brillouin zone, in contrast with the LDA band calculation but in good agreement with the GW calculation. This requests reexamination of the excitonic-insulator model based on an overlap of an electron and a hole band at the X point. In DVB 2C2, we found two (one electron-like and one hole-like) Fermi surfaces, which are composed of the mixed states of the B2p, C2p and Dy5d orbitals, below the antiferro-quadrupolar-ordering temperature.",

keywords = "CaBe, DybB, Fermi surface, MgB, Photoemission spectroscopy",

author = "Takashi Takahashi and Seigo Soma and Takafumi Sato",

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T1 - Angle-resolved photoemission study of novel boride compounds

AU - Takahashi, Takashi

AU - Soma, Seigo

AU - Sato, Takafumi

PY - 2002/12/1

Y1 - 2002/12/1

N2 - We have performed high-resolution photoemission spectroscopy on newly discovered novel boride compounds, MgB2, La-doped CaB6, and DVB2C2. In MgB2, we observed the superconducting gap of about 4.5 meV with s-wave symmetry. In La-doped CaB 6, we found a 1 eV energy gap at the X point in the Brillouin zone, in contrast with the LDA band calculation but in good agreement with the GW calculation. This requests reexamination of the excitonic-insulator model based on an overlap of an electron and a hole band at the X point. In DVB 2C2, we found two (one electron-like and one hole-like) Fermi surfaces, which are composed of the mixed states of the B2p, C2p and Dy5d orbitals, below the antiferro-quadrupolar-ordering temperature.

AB - We have performed high-resolution photoemission spectroscopy on newly discovered novel boride compounds, MgB2, La-doped CaB6, and DVB2C2. In MgB2, we observed the superconducting gap of about 4.5 meV with s-wave symmetry. In La-doped CaB 6, we found a 1 eV energy gap at the X point in the Brillouin zone, in contrast with the LDA band calculation but in good agreement with the GW calculation. This requests reexamination of the excitonic-insulator model based on an overlap of an electron and a hole band at the X point. In DVB 2C2, we found two (one electron-like and one hole-like) Fermi surfaces, which are composed of the mixed states of the B2p, C2p and Dy5d orbitals, below the antiferro-quadrupolar-ordering temperature.

KW - CaBe

KW - DybB

KW - Fermi surface

KW - MgB

KW - Photoemission spectroscopy

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Angle-resolved photoemission study of novel boride compounds

Abstract

Keywords

ASJC Scopus subject areas

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