The Physical Society of JapanActa Medica Okayama0031-901579122010Electronic Structure of the Novel Filled Skutterudite PrPt<sub>4</sub>Ge<sub>12</sub> Superconductor124701-1124701-4ENYoshiakiNakamuraHiroyukiOkazakiRikiyaYoshidaTakanoriWakitaMasaakiHiraiYujiMuraokaHiroyukiTakeyaKazutoHirataHiroshiKumigashiraMasaharuOshimaTakayoshiYokoyaWe have performed soft x-ray photoemission spectroscopy (SXPES) and resonant photoemission spectroscopy (RPES) of the filled skutterudite superconductor PrPt<sub>4</sub>Ge<sub>12</sub> in order to study the electronic structure of valence band and the character of Pr 4f. SXPES of PrPt<sub>4</sub>Ge<sub>12</sub> measured with 1200 eV photon energy, where spectral contribution of Pr 4f is negligible, was found nearly identical with that of LaPt<sub>4</sub>Ge<sub>12</sub>, indicating similarity of Pt–Ge derived electronic states of the two compounds. Good correspondence with band calculations allows us to ascribe the dominant Ge 4p character of the density of states at the Fermi level (E<sub>F</sub>). Pr 3d 4f RPES shows that, although Pr 4f electrons in PrPt<sub>4</sub>Ge<sub>12</sub> are not as strongly hybridized with conduction electrons near E<sub>F</sub> as in PrFe4P12, there are finite Pr 4f contribution to the states near E<sub>F</sub> in PrPt<sub>4</sub>Ge<sub>12</sub>. These PES results give the information of fundamental electronic structure for understanding the physical properties of the novel filled skutterudite superconductor PrPt<sub>4</sub>Ge<sub>12</sub>.No potential conflict of interest relevant to this article was reported.The Physical Society of JapanActa Medica Okayama0031-90158152012Superconductivity Induced by Bond Breaking in the Triangular Lattice of IrTe2053701-1053701-4ENSunsengPyonKazutakaKudoMinoruNoharaIrTe2, a layered compound with a triangular iridium lattice, exhibits a structural phase transition at approximately 250 K. This transition is characterized by the formation of Ir-Ir bonds along the b-axis. We found that the breaking of Ir-Ir bonds that occurs in Ir1-xPtxTe2 results in the appearance of a structural critical point in the T = 0 limit at x(c) similar or equal to 0.035. Although both IrTe2 and PtTe2 are paramagnetic metals, superconductivity at T-c = 3.1 K is induced by the bond breaking in a narrow range of x >= x(c) in Ir1-xPtxTe2. This result indicates that structural fluctuations can be involved in the emergence of superconductivity.No potential conflict of interest relevant to this article was reported.