抄録
We have studied disorder-induced in-gap states and effect of light illumination in the insulating phase of spinel-type CuIr2S 4 using ultraviolet photoemission spectroscopy (UPS). The Ir 3+/Ir4+ charge-ordered gap appears below the metal-insulator transition temperature. However, in the insulating phase, in-gap spectral features with softgap are observed in UPS just below the Fermi level (EF), corresponding to the variable range hopping transport observed in resistivity. The spectral weight at EF is not increased by light illumination, indicating that the Ir4+-Ir4+ dimer is very robust, although the long-range octamer order would be destructed by the photoexcitation. Present results suggest that the Ir4+-Ir 4+ bipolaronic hopping and disorder effects are responsible for the conductivity of CuIr2S4.
| 元の言語 | English |
|---|---|
| 記事番号 | 245117 |
| ジャーナル | Physical Review B - Condensed Matter and Materials Physics |
| 巻 | 78 |
| 発行部数 | 24 |
| DOI | |
| 出版物ステータス | Published - 2008 12 1 |
| 外部発表 | Yes |
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ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials
これを引用
In-gap state and effect of light illumination in CuIr2S 4 probed by photoemission spectroscopy. / Takubo, K.; Mizokawa, Takashi; Matsumoto, N.; Nagata, S.
：: Physical Review B - Condensed Matter and Materials Physics, 巻 78, 番号 24, 245117, 01.12.2008.研究成果: Article
}
TY - JOUR
T1 - In-gap state and effect of light illumination in CuIr2S 4 probed by photoemission spectroscopy
AU - Takubo, K.
AU - Mizokawa, Takashi
AU - Matsumoto, N.
AU - Nagata, S.
PY - 2008/12/1
Y1 - 2008/12/1
N2 - We have studied disorder-induced in-gap states and effect of light illumination in the insulating phase of spinel-type CuIr2S 4 using ultraviolet photoemission spectroscopy (UPS). The Ir 3+/Ir4+ charge-ordered gap appears below the metal-insulator transition temperature. However, in the insulating phase, in-gap spectral features with softgap are observed in UPS just below the Fermi level (EF), corresponding to the variable range hopping transport observed in resistivity. The spectral weight at EF is not increased by light illumination, indicating that the Ir4+-Ir4+ dimer is very robust, although the long-range octamer order would be destructed by the photoexcitation. Present results suggest that the Ir4+-Ir 4+ bipolaronic hopping and disorder effects are responsible for the conductivity of CuIr2S4.
AB - We have studied disorder-induced in-gap states and effect of light illumination in the insulating phase of spinel-type CuIr2S 4 using ultraviolet photoemission spectroscopy (UPS). The Ir 3+/Ir4+ charge-ordered gap appears below the metal-insulator transition temperature. However, in the insulating phase, in-gap spectral features with softgap are observed in UPS just below the Fermi level (EF), corresponding to the variable range hopping transport observed in resistivity. The spectral weight at EF is not increased by light illumination, indicating that the Ir4+-Ir4+ dimer is very robust, although the long-range octamer order would be destructed by the photoexcitation. Present results suggest that the Ir4+-Ir 4+ bipolaronic hopping and disorder effects are responsible for the conductivity of CuIr2S4.
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U2 - 10.1103/PhysRevB.78.245117
DO - 10.1103/PhysRevB.78.245117
M3 - Article
VL - 78
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 0163-1829
IS - 24
M1 - 245117
ER -