start-ver=1.4 cd-journal=joma no-vol=81 cd-vols= no-issue=5 article-no= start-page=053701-1 end-page=053701-4 dt-received= dt-revised= dt-accepted= dt-pub-year=2012 dt-pub=20120406 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Superconductivity Induced by Bond Breaking in the Triangular Lattice of IrTe2 en-subtitle= kn-subtitle= en-abstract= kn-abstract=IrTe2, 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. en-copyright= kn-copyright= en-aut-name=PyonSunseng en-aut-sei=Pyon en-aut-mei=Sunseng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KudoKazutaka en-aut-sei=Kudo en-aut-mei=Kazutaka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NoharaMinoru en-aut-sei=Nohara en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Physics, Faculty of Science, Okayama University affil-num=2 en-affil= kn-affil=Department of Physics, Faculty of Science, Okayama University affil-num=3 en-affil= kn-affil=Department of Physics, Faculty of Science, Okayama University en-keyword=superconductivity kn-keyword=superconductivity en-keyword=IrTe2 kn-keyword=IrTe2 en-keyword=Pt doping kn-keyword=Pt doping en-keyword=triangular lattice kn-keyword=triangular lattice en-keyword=phase diagram kn-keyword=phase diagram en-keyword=structural phase transition kn-keyword=structural phase transition END start-ver=1.4 cd-journal=joma no-vol=152 cd-vols= no-issue=8 article-no= start-page=635 end-page=639 dt-received= dt-revised= dt-accepted= dt-pub-year=2012 dt-pub=201204 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Iron?platinum?arsenide superconductors Ca10(PtnAs8)(Fe2?xPtxAs2)5 en-subtitle= kn-subtitle= en-abstract= kn-abstract=An overview of the crystal structures and physical properties of the recently discovered iron-platinum-arsenide superconductors, Ca-10(PtnAs8)(Fe2-xPtxAs2)(5) (n = 3 and 4), which have a superconducting transition temperature up to 38K, is provided. The crystal structure consists of superconducting Fe2As2 layers alternating with platinum-arsenic layers, PtnAs8. The upper critical field H-c2, hydrostatic pressure dependence of superconducting transition temperature T-c, and normal-state magnetic susceptibility are reported. en-copyright= kn-copyright= en-aut-name=NoharaMinoru en-aut-sei=Nohara en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KakiyaSatomi en-aut-sei=Kakiya en-aut-mei=Satomi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KudoKazutaka en-aut-sei=Kudo en-aut-mei=Kazutaka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=OshiroYoshihiro en-aut-sei=Oshiro en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=ArakiShingo en-aut-sei=Araki en-aut-mei=Shingo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KobayashiTatsuo C. en-aut-sei=Kobayashi en-aut-mei=Tatsuo C. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=OkuKenta en-aut-sei=Oku en-aut-mei=Kenta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=NishiboriEiji en-aut-sei=Nishibori en-aut-mei=Eiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=SawaHiroshi en-aut-sei=Sawa en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil= kn-affil=Department of Physics, Okayama University affil-num=2 en-affil= kn-affil=Department of Physics, Okayama University affil-num=3 en-affil= kn-affil=Department of Physics, Okayama University affil-num=4 en-affil= kn-affil=Department of Physics, Okayama University affil-num=5 en-affil= kn-affil=Department of Physics, Okayama University affil-num=6 en-affil= kn-affil=Department of Physics, Okayama University affil-num=7 en-affil= kn-affil=Department of Applied Physics, Nagoya University affil-num=8 en-affil= kn-affil=Department of Applied Physics, Nagoya University affil-num=9 en-affil= kn-affil=Department of Applied Physics, Nagoya University en-keyword=A. Iron-based superconductors kn-keyword=A. Iron-based superconductors en-keyword=E. Transport kn-keyword=E. Transport en-keyword=E. High pressure kn-keyword=E. High pressure END start-ver=1.4 cd-journal=joma no-vol=100 cd-vols= no-issue=25 article-no= start-page=252104-1 end-page=252104-3 dt-received= dt-revised= dt-accepted= dt-pub-year=2012 dt-pub=20120619 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Enhanced thermoelectric properties by Ir doping of PtSb2 with pyrite structure en-subtitle= kn-subtitle= en-abstract= kn-abstract=The effects of Ir doping on the thermoelectric properties of Pt1-xIrxSb2 (x = 0, 0.01, 0.03, and 0.1) with pyrite structure were studied. Measurements of electrical resistivity rho, Seebeck coefficient S, and thermal conductivity kappa were conducted. The results showed an abrupt change from semiconducting behavior without Ir (x = 0) to metallic behavior at x = 0.01. The sample with x = 0.01 exhibited large S and low rho, resulting in a maximum power factor (S-2/rho) of 43 mu W/cmK(2) at 400 K. The peculiar "pudding mold"-type electronic band dispersion could explain the enhanced thermoelectric properties in the metallic state. en-copyright= kn-copyright= en-aut-name=NishikuboYoshihiro en-aut-sei=Nishikubo en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NakanoSeiya en-aut-sei=Nakano en-aut-mei=Seiya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KudoKazutaka en-aut-sei=Kudo en-aut-mei=Kazutaka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NoharaMinoru en-aut-sei=Nohara en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Department of Physics, Okayama University affil-num=2 en-affil= kn-affil=Department of Physics, Okayama University affil-num=3 en-affil= kn-affil=Department of Physics, Okayama University affil-num=4 en-affil= kn-affil=Department of Physics, Okayama University END