Photo-control of charge and orbital states in transition-metal compounds porobed by photoemission spectroscopy

K. Takubo, J. Y. Son, Takashi Mizokawa, N. Takubo, K. Miyano, N. Matsumoto, S. Nagata

Research output: Contribution to journalArticle

Abstract

We have studied the charge-orbital states in spinel- type CuIr 2S 4 and perovskite-type Pr 0.55(Ca 1-y Sr y ) 0.45MnO 3 (PCSMO, y=0.25, 0.40) using X-ray photoemission spectroscopy (XPS) combined with laser illumination. The XPS data of CuIr 2S 4 are dramatically changed by the insulator-metal transition (IMT). The line shape of CuIr 2S 4 in the insulating phase is consistent with the charge disproportionation of Ir 3+:Ir 4+=1:1. Interestingly, a visible light irradiation at low temperature gives a resistance reduction but does not give any spectral change. In case of PCSMO, the IMT is also clearly observed on the XPS data and the peculiar temperature dependence for y=0.25 suggests the coexisting of the ferromagnetic metallic phase and the charge-orbital ordered insulating phase. The spectra after visible light illumination show the enhancement of the density of states at the Fermi level, accompanied with the drop of the resistance.

Original languageEnglish
Pages (from-to)635-638
Number of pages4
JournalJournal of Superconductivity and Novel Magnetism
Volume20
Issue number7-8
DOIs
Publication statusPublished - 2007 Nov
Externally publishedYes

Fingerprint

Transition metal compounds
metal compounds
Photoelectron spectroscopy
X ray spectroscopy
Metal insulator transition
photoelectric emission
transition metals
orbitals
Lighting
illumination
insulators
spectroscopy
x rays
visible spectrum
Fermi level
Perovskite
spinel
line shape
Irradiation
Temperature

Keywords

  • Phase competition
  • Photo-induced phase transition
  • Photoemission

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Photo-control of charge and orbital states in transition-metal compounds porobed by photoemission spectroscopy. / Takubo, K.; Son, J. Y.; Mizokawa, Takashi; Takubo, N.; Miyano, K.; Matsumoto, N.; Nagata, S.

In: Journal of Superconductivity and Novel Magnetism, Vol. 20, No. 7-8, 11.2007, p. 635-638.

Research output: Contribution to journalArticle

Takubo, K. ; Son, J. Y. ; Mizokawa, Takashi ; Takubo, N. ; Miyano, K. ; Matsumoto, N. ; Nagata, S. / Photo-control of charge and orbital states in transition-metal compounds porobed by photoemission spectroscopy. In: Journal of Superconductivity and Novel Magnetism. 2007 ; Vol. 20, No. 7-8. pp. 635-638.
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AU - Son, J. Y.

AU - Mizokawa, Takashi

AU - Takubo, N.

AU - Miyano, K.

AU - Matsumoto, N.

AU - Nagata, S.

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N2 - We have studied the charge-orbital states in spinel- type CuIr 2S 4 and perovskite-type Pr 0.55(Ca 1-y Sr y ) 0.45MnO 3 (PCSMO, y=0.25, 0.40) using X-ray photoemission spectroscopy (XPS) combined with laser illumination. The XPS data of CuIr 2S 4 are dramatically changed by the insulator-metal transition (IMT). The line shape of CuIr 2S 4 in the insulating phase is consistent with the charge disproportionation of Ir 3+:Ir 4+=1:1. Interestingly, a visible light irradiation at low temperature gives a resistance reduction but does not give any spectral change. In case of PCSMO, the IMT is also clearly observed on the XPS data and the peculiar temperature dependence for y=0.25 suggests the coexisting of the ferromagnetic metallic phase and the charge-orbital ordered insulating phase. The spectra after visible light illumination show the enhancement of the density of states at the Fermi level, accompanied with the drop of the resistance.

AB - We have studied the charge-orbital states in spinel- type CuIr 2S 4 and perovskite-type Pr 0.55(Ca 1-y Sr y ) 0.45MnO 3 (PCSMO, y=0.25, 0.40) using X-ray photoemission spectroscopy (XPS) combined with laser illumination. The XPS data of CuIr 2S 4 are dramatically changed by the insulator-metal transition (IMT). The line shape of CuIr 2S 4 in the insulating phase is consistent with the charge disproportionation of Ir 3+:Ir 4+=1:1. Interestingly, a visible light irradiation at low temperature gives a resistance reduction but does not give any spectral change. In case of PCSMO, the IMT is also clearly observed on the XPS data and the peculiar temperature dependence for y=0.25 suggests the coexisting of the ferromagnetic metallic phase and the charge-orbital ordered insulating phase. The spectra after visible light illumination show the enhancement of the density of states at the Fermi level, accompanied with the drop of the resistance.

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