start-ver=1.4 cd-journal=joma no-vol=7 cd-vols= no-issue=3 article-no= start-page=036001 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200316 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Inhomogeneous superconductivity in thin crystals of FeSe1-xTex (x=1.0, 0.95, and 0.9) en-subtitle= kn-subtitle= en-abstract= kn-abstract=We investigated the temperature dependence of resistivity in thin crystals of FeSe1-xTex (x = 1.0, 0.95, and 0.9), though bulk crystals with 1.0 x 0.9 are known to be non-superconducting. With decreasing thickness of the crystals, the resistivity of x = 0.95 and 0.9 decreases and reaches zero at a low temperature, which indicates a clear superconducting transition. The anomaly of resistivity related to the structural and magnetic transitions completely disappears in 55- to 155-nm-thick crystals of x = 0.9, resulting in metallic behavior in the normal state. Microbeam x-ray diffraction measurements were performed on bulk single crystals and thin crystals of FeSe1-xTex. A significant difference of the lattice constant, c, was observed in FeSe1-xTex, which varied with differing Te content (x), and even in crystals with the same x, which was mainly caused by inhomogeneity of the Se/Te distribution. It has been found that the characteristic temperatures causing the structural and magnetic transition (T-t), the superconducting transition (T-c), and the zero resistivity (T-c(zero)) are closely related to the value of c in thin crystals of FeSe1-xTex. en-copyright= kn-copyright= en-aut-name=EguchiRitsuko en-aut-sei=Eguchi en-aut-mei=Ritsuko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SendaMegumi en-aut-sei=Senda en-aut-mei=Megumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UesugiEri en-aut-sei=Uesugi en-aut-mei=Eri kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=GotoHidenori en-aut-sei=Goto en-aut-mei=Hidenori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=FujiwaraAkihiko en-aut-sei=Fujiwara en-aut-mei=Akihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=ImaiYasuhiko en-aut-sei=Imai en-aut-mei=Yasuhiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KimuraShigeru en-aut-sei=Kimura en-aut-mei=Shigeru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=NojiTakashi en-aut-sei=Noji en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=KoikeYoji en-aut-sei=Koike en-aut-mei=Yoji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=KubozonoYoshihiro en-aut-sei=Kubozono en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=5 en-affil=Department of Nanotechnology for Sustainable Energy, Kwansei Gakuin University kn-affil= affil-num=6 en-affil=Japan Synchrotron Radiation Research Institute (JASRI) kn-affil= affil-num=7 en-affil=Japan Synchrotron Radiation Research Institute (JASRI) kn-affil= affil-num=8 en-affil=Department of Applied Physics, Tohoku University kn-affil= affil-num=9 en-affil=Department of Applied Physics, Tohoku University kn-affil= affil-num=10 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= en-keyword=iron-based superconductor kn-keyword=iron-based superconductor en-keyword=thin crystals kn-keyword=thin crystals en-keyword=microbeam XRD kn-keyword=microbeam XRD END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue= article-no= start-page=4009 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=201938 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Synthesis of the extended phenacene molecules, [10]phenacene and [11]phenacene, and their performance in a field-effect transistor en-subtitle= kn-subtitle= en-abstract= kn-abstract= The [10]phenacene and [11]phenacene molecules have been synthesized using a simple repetition of Wittig reactions followed by photocyclization. Sufficient amounts of [10]phenacene and [11]phenacene were obtained, and thin-film FETs using these molecules have been fabricated with SiO2 and ionic liquid gate dielectrics. These FETs operated in p-channel. The averaged measurements of field-effect mobility, <>, were 3.1(7)?~?10-2 and 1.11(4)?~?10-1?cm2 V-1 s-1, respectively, for [10]phenacene and [11]phenacene thin-film FETs with SiO2 gate dielectrics. Furthermore, [10]phenacene and [11]phenacene thin-film electric-double-layer (EDL) FETs with ionic liquid showed low-voltage p-channel FET properties, with <> values of 3(1) and 1(1)?cm2 V-1 s-1, respectively. This study also discusses the future utility of the extremely extended -network molecules [10]phenacene and [11]phenacene as the active layer of FET devices, based on the experimental results obtained. en-copyright= kn-copyright= en-aut-name=OkamotoHideki en-aut-sei=Okamoto en-aut-mei=Hideki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HamaoShino en-aut-sei=Hamao en-aut-mei=Shino kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=EguchiRitsuko en-aut-sei=Eguchi en-aut-mei=Ritsuko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=GotoHidenori en-aut-sei=Goto en-aut-mei=Hidenori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TakabayashiYasuhiro en-aut-sei=Takabayashi en-aut-mei=Yasuhiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=YenPaul Yu-Hsiang en-aut-sei=Yen en-aut-mei=Paul Yu-Hsiang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=LiangLuo Uei en-aut-sei=Liang en-aut-mei=Luo Uei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=ChouChia-Wei en-aut-sei=Chou en-aut-mei=Chia-Wei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=HoffmannGermar en-aut-sei=Hoffmann en-aut-mei=Germar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=GohdaShin en-aut-sei=Gohda en-aut-mei=Shin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=SuginoHisako en-aut-sei=Sugino en-aut-mei=Hisako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=LiaosYen-Fa en-aut-sei=Liaos en-aut-mei=Yen-Fa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=IshiiHirofumi en-aut-sei=Ishii en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=KubozonoYoshihiro en-aut-sei=Kubozono en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= affil-num=1 en-affil= Department of Chemistry, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=5 en-affil= Department of Chemistry, Okayama University kn-affil= affil-num=6 en-affil=Department of Physics, National Tsing Hua University kn-affil= affil-num=7 en-affil=Department of Physics, National Tsing Hua University kn-affil= affil-num=8 en-affil=Department of Physics, National Tsing Hua University kn-affil= affil-num=9 en-affil=Department of Physics, National Tsing Hua University kn-affil= affil-num=10 en-affil=NARD Co Ltd kn-affil= affil-num=11 en-affil=NARD Co Ltd kn-affil= affil-num=12 en-affil=National Synchrotron Radiation Center kn-affil= affil-num=13 en-affil=National Synchrotron Radiation Center kn-affil= affil-num=14 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=3 cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2013 dt-pub=20130413 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Electric double-layer capacitance between an ionic liquid and few-layer graphene en-subtitle= kn-subtitle= en-abstract= kn-abstract=Ionic-liquid gates have a high carrier density due to their atomically thin electric double layer (EDL) and extremely large geometrical capacitance C-g. However, a high carrier density in graphene has not been achieved even with ionic-liquid gates because the EDL capacitance C-EDL between the ionic liquid and graphene involves the series connection of C-g and the quantum capacitance C-q, which is proportional to the density of states. We investigated the variables that determine C-EDL at the molecular level by varying the number of graphene layers n and thereby optimising C-q. The C-EDL value is governed by C-q at n, 4, and by C-g at n > 4. This transition with n indicates a composite nature for C-EDL. Our finding clarifies a universal principle that determines capacitance on a microscopic scale, and provides nanotechnological perspectives on charge accumulation and energy storage using an ultimately thin capacitor. en-copyright= kn-copyright= en-aut-name=UesugiEri en-aut-sei=Uesugi en-aut-mei=Eri kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=GotoHidenori en-aut-sei=Goto en-aut-mei=Hidenori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=EguchiRitsuko en-aut-sei=Eguchi en-aut-mei=Ritsuko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=FujiwaraAkihiko en-aut-sei=Fujiwara en-aut-mei=Akihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KubozonoYoshihiro en-aut-sei=Kubozono en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Okayama Univ, Surface Sci Res Lab affil-num=2 en-affil= kn-affil=Okayama Univ, Surface Sci Res Lab affil-num=3 en-affil= kn-affil=Okayama Univ, Surface Sci Res Lab affil-num=4 en-affil= kn-affil=SPring 8, Japan Synchrotron Radiat Res Inst affil-num=5 en-affil= kn-affil=Okayama Univ, Surface Sci Res Lab END start-ver=1.4 cd-journal=joma no-vol=88 cd-vols= no-issue=9 article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2012 dt-pub=20120930 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Superconductivity in (NH3)(y)Cs0.4FeSe en-subtitle= kn-subtitle= en-abstract= kn-abstract=Alkali-metal-intercalated FeSe materials, (NH3)(y)M0.4FeSe (M: K, Rb, and Cs), have been synthesized using the liquid NH3 technique. (NH3)(y)Cs0.4FeSe shows a superconducting transition temperature (T-c) as high as 31.2 K, which is higher by 3.8 K than the T-c of nonammoniated Cs0.4FeSe. The T(c)s of (NH3)(y)K0.4FeSe and (NH3)(y)Rb0.4FeSe are almost the same as those of nonammoniated K0.4FeSe and Rb0.4FeSe. The T-c of (NH3)(y)Cs0.4FeSe shows a negative pressure dependence. A clear correlation between T-c and lattice constant c is found for ammoniated metal-intercalated FeSe materials, suggesting a correlation between Fermi-surface nesting and superconductivity. en-copyright= kn-copyright= en-aut-name=ZhengLu en-aut-sei=Zheng en-aut-mei=Lu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=IzumiMasanari en-aut-sei=Izumi en-aut-mei=Masanari kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SakaiYusuke en-aut-sei=Sakai en-aut-mei=Yusuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=EguchiRitsuko en-aut-sei=Eguchi en-aut-mei=Ritsuko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=GotoHidenori en-aut-sei=Goto en-aut-mei=Hidenori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=TakabayashiYasuhiro en-aut-sei=Takabayashi en-aut-mei=Yasuhiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KambeTakashi en-aut-sei=Kambe en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=OnjiTaiki en-aut-sei=Onji en-aut-mei=Taiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 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=9 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=10 ORCID= en-aut-name=KimJungeun en-aut-sei=Kim en-aut-mei=Jungeun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=FujiwaraAkihiko en-aut-sei=Fujiwara en-aut-mei=Akihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=KubozonoYoshihiro en-aut-sei=Kubozono en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= affil-num=1 en-affil= kn-affil=Okayama Univ, Res Lab Surface Sci affil-num=2 en-affil= kn-affil=Okayama Univ, Res Lab Surface Sci affil-num=3 en-affil= kn-affil=Okayama Univ, Res Lab Surface Sci affil-num=4 en-affil= kn-affil=Okayama Univ, Res Lab Surface Sci affil-num=5 en-affil= kn-affil=Okayama Univ, Res Lab Surface Sci affil-num=6 en-affil= kn-affil=Okayama Univ, Res Lab Surface Sci affil-num=7 en-affil= kn-affil=Okayama Univ, Dept Phys affil-num=8 en-affil= kn-affil=Okayama Univ, Dept Phys affil-num=9 en-affil= kn-affil=Okayama Univ, Dept Phys affil-num=10 en-affil= kn-affil=Okayama Univ, Dept Phys affil-num=11 en-affil= kn-affil=RIKEN, SPring Ctr 8, Japan Synchrotron Radiat Res Inst affil-num=12 en-affil= kn-affil=RIKEN, SPring Ctr 8, Japan Synchrotron Radiat Res Inst affil-num=13 en-affil= kn-affil=Okayama Univ, Res Lab Surface Sci END