The American Physical SocietyActa Medica Okayama1098-012190222014Proximity to Fermi-surface topological change in superconducting LaO0.54F0.46BiS2ENKenseiTerashimaJunkiSonoyamaTakanoriWakitaMasanoriSunagawaKantaOnoHiroshiKumigashiraTakayukiMuroMasanoriNagaoSatoshiWatauchiIsaoTanakaHiroyukiOkazakiYoshihikoTakanoOsukeMiuraYoshikazuMizuguchiHidetomoUsuiKatsuhiroSuzukiKazuhikoKurokiYujiMuraokaTakayoshiYokoyaThe electronic structure of nearly optimally doped novel superconductor LaO1|xFxBiS2(x = 0.46) was investigated using angle-resolved photoemission spectroscopy (ARPES). We clearly observed band dispersions from 2 to 6 eV binding energy and near the Fermi level (EF), which are well reproduced by first-principles calculations when the spin-orbit coupling is taken into account. The ARPES intensity map near EF shows a squarelike distribution around the (Z) point in addition to electronlike Fermi-surface (FS) sheets around the X(R) point, indicating that FS of LaO0.54F0.46BiS2 is in close proximity to the theoretically predicted topological change.No potential conflict of interest relevant to this article was reported.American Physical SocietyActa Medica Okayama2469-99509642017Evolution of the remnant Fermi-surface state in the lightly doped correlated spin-orbit insulator Sr2-xLaxIrO4041106ENKenseiTerashimaResearch Institute for Interdisciplinary Science, Okayama UniversityM.SunagawaGraduate School of Natural Sciences, Okayama UniversityH.FujiwaraGraduate School of Natural Sciences, Okayama UniversityT.FukuraM.FujiiGraduate School of Natural Sciences, Okayama UniversityK.OkadaAoyama Gakuin UniversityK.HoriganeResearch Institute for Interdisciplinary Science, Okayama UniversityK.KobayashiResearch Institute for Interdisciplinary Science, Okayama UniversityR.HorieResearch Institute for Interdisciplinary Science, Okayama UniversityJ.AkimitsuResearch Institute for Interdisciplinary Science, Okayama UniversityE.GoliasHelmholtz-Zentrum Berlin für Materialien und EnergieD.MarchenkoHelmholtz-Zentrum Berlin für Materialien und EnergieA.VarykhalovHelmholtz-Zentrum Berlin für Materialien und EnergieN. L.SainiDipartimento di Fisica, Universitá di Roma gLa SapienzaT.WakitaResearch Institute for Interdisciplinary Science, Okayama UniversityY.MuraokaResearch Institute for Interdisciplinary Science, Okayama UniversityT.YokoyaResearch Institute for Interdisciplinary Science, Okayama University The electronic structure of the lightly electron-doped correlated spin-orbit insulator Sr2IrO4 has been studied by angle-resolved photoelectron spectroscopy. We have observed the coexistence of a lower Hubbard band and an in-gap band; the momentum dependence of the latter traces that of the band calculations without on-site Coulomb repulsion. The in-gap state remained anisotropically gapped in all observed momentum areas, forming a remnant Fermi-surface state, evolving towards the Fermi energy by carrier doping. These experimental results show a striking similarity with those observed in deeply underdoped cuprates, suggesting the common nature of the nodal liquid states observed in both compounds.No potential conflict of interest relevant to this article was reported.American Chemical SocietyActa Medica Okayama153069841992019Asymmetric Phosphorus Incorporation in Homoepitaxial P-Doped (111) Diamond Revealed by Photoelectron Holography59155919ENT.YokoyaResearch Institute for Interdisciplinary Science (RIIS), Okayama UniversityK.TerashimaResearch Institute for Interdisciplinary Science (RIIS), Okayama UniversityA.TakedaGraduate School of Science and Technology, Okayama UniversityT.FukuraGraduate School of Science and Technology, Okayama UniversityH.FujiwaraGraduate School of Science and Technology, Okayama UniversityT.MuroJapan Synchrotron Radiation Research Institute (JASRI)/SPring-8T.KinoshitaJapan Synchrotron Radiation Research Institute (JASRI)/SPring-8H.KatoEnergy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)S.YamasakiEnergy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)T.OguchiInstitute of Scientific and Industrial Research, Osaka UniversityT.WakitaResearch Institute for Interdisciplinary Science (RIIS), Okayama UniversityY.MuraokaResearch Institute for Interdisciplinary Science (RIIS), Okayama UniversityT.MatsushitaJapan Synchrotron Radiation Research Institute (JASRI)/SPring-8 Diamond has two crystallographically inequivalent sites in the unit cell. In doped diamond, dopant occupation in the two sites is expected to be equal. Nevertheless, preferential dopant occupation during growth under nonequilibrium conditions is of fundamental importance, for example, to enhance the properties of nitrogen-vacancy (N-V) centers; therefore, this is a promising candidate for a qubit. However, the lack of suitable experimental techniques has made it difficult to study the crystal- and chemical-site-resolved local structures of dopants. Here, we confirm the identity of two chemical sites with asymmetric dopant incorporation in the diamond structure, via the photoelectron holography (PEH) of heavily phosphorus (P)-doped diamond prepared by chemical vapor deposition. One is substitutionally incorporated P with preferential site occupations and the other can be attributed to a PV split vacancy complex with preferential orientation. The present study shows that PEH is a valuable technique to study the local structures around dopants with a resolution of crystallographically inequivalent but energetically equivalent sites/orientations. Such information provides strategies to improve the properties of dopant related-complexes in which alignment is crucial for sensing of magnetic field or quantum spin register using N-V centers in diamond.No potential conflict of interest relevant to this article was reported.Nature Publishing GroupActa Medica Okayama2045-232292019Fermi level tuning of Ag-doped Bi2Se3 topological insulator5376ENEriUesugiResearch Institute for Interdisciplinary Science, Okayama UniversityTakakiUchiyamaResearch Institute for Interdisciplinary Science, Okayama UniversityHidenoriGotoResearch Institute for Interdisciplinary Science, Okayama UniversityHiromiOta Advanced Science Research Centre, Okayama UniversityTeppeiUenoResearch Institute for Interdisciplinary Science, Okayama UniversityHirokazuFujiwaraResearch Institute for Interdisciplinary Science, Okayama UniversityKenseiTerashimaResearch Institute for Interdisciplinary Science, Okayama UniversityTakayoshiYokoyaResearch Institute for Interdisciplinary Science, Okayama UniversityFumihikoMatsuiGraduate School of Materials Science, Nara Institute of Science and TechnologyJunAkimitsuResearch Institute for Interdisciplinary Science, Okayama UniversityKayaKobayashiResearch Institute for Interdisciplinary Science, Okayama UniversityYoshihiroKubozonoResearch Institute for Interdisciplinary Science, Okayama UniversityThe temperature dependence of the resistivity (rho) of Ag-doped Bi2Se3 (AgxBi2-xSe3) shows insulating behavior above 35 K, but below 35 K, rho suddenly decreases with decreasing temperature, in contrast to the metallic behavior for non-doped Bi2Se3 at 1.5-300 K. This significant change in transport properties from metallic behavior clearly shows that the Ag doping of Bi2Se3 can effectively tune the Fermi level downward. The Hall effect measurement shows that carrier is still electron in AgxBi2-xSe3 and the electron density changes with temperature to reasonably explain the transport properties. Furthermore, the positive gating of AgxBi2-xSe3 provides metallic behavior that is similar to that of non-doped Bi2Se3, indicating a successful upward tuning of the Fermi level.No potential conflict of interest relevant to this article was reported.ElsevierActa Medica Okayama0040-60906982020Strain effects on spinodal decomposition in TiO2-VO(2)films on TiO2(100) substrates137854ENYujiMuraokaResearch Institute for Interdisciplinary Science (RIIS), Okayama UniversityFumiyaYoshiiGraduate School of Natural Science and Technology, Okayama UniversityTakahiroFukudaGraduate School of Natural Science and Technology, Okayama UniversityYujiManabeGraduate School of Natural Science and Technology, Okayama UniversityMikikoYasunoGraduate School of Natural Science and Technology, Okayama UniversityYoshitoTakemotoGraduate School of Natural Science and Technology, Okayama UniversityKenseiTerashimaResearch Institute for Interdisciplinary Science, Okayama UniversityTakanoriWakitaResearch Institute for Interdisciplinary Science (RIIS), Okayama UniversityTakayoshiYokoya We investigate the influence of lattice strain in the c-axis direction on spinodal decomposition in rutile TiO2-VO2 films on TiO2(100) substrates. The [100]-oriented Ti0.4V0.6O2 (TVO) solid-solution films are fabricated on rutile TiO2(100) substrates using a pulsed laser deposition with a KrF excimer laser, and are annealed inside the spinodal region. X-ray diffraction and scanning transmission electron microscopy are employed for characterization. Consequently, the in-plane tensile strain in the c-axis direction promotes the Ti-V interdiffusion in TVO/TiO2(100) under thermal annealing. In contrast, relaxation of the tensile strain results in the occurrence of spinodal decomposition along the c-axis direction in the film. These results indicate that the relaxation of the tensile strain in the c-axis direction is critically important for enabling spinodal decomposition in TVO/TiO2(100). Our work helps deepen the understanding of spinodal decomposition in the TVO film and provides information on achieving novel nanostructures via spinodal decomposition in TVO/TiO2(100).No potential conflict of interest relevant to this article was reported.