TY - JOUR
T1 - Photo-control of charge and orbital states in transition-metal compounds porobed by photoemission spectroscopy
AU - Takubo, K.
AU - Son, J. Y.
AU - Mizokawa, T.
AU - Takubo, N.
AU - Miyano, K.
AU - Matsumoto, N.
AU - Nagata, S.
PY - 2007/11/1
Y1 - 2007/11/1
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.
KW - Phase competition
KW - Photo-induced phase transition
KW - Photoemission
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U2 - 10.1007/s10948-007-0248-1
DO - 10.1007/s10948-007-0248-1
M3 - Article
AN - SCOPUS:36049018662
SN - 1557-1939
VL - 20
SP - 635
EP - 638
JO - Journal of Superconductivity and Novel Magnetism
JF - Journal of Superconductivity and Novel Magnetism
IS - 7-8
ER -