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

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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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
Issue number7-8
Publication statusPublished - 2007 Nov 1
Externally publishedYes


  • Phase competition
  • Photo-induced phase transition
  • Photoemission

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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