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Tomassucci G, Tortora L, Pugliese GM, Stramaglia F, Simonelli L, Marini C, Terashima K, Wakita T, Ayukawa S, Yokoya T, Kudo K, Nohara M, Mizokawa T, Saini NL. Temperature dependent local inhomogeneity and magnetic moments of (Li 1-xFe x)OHFeSe superconductors. Phys Chem Chem Phys 2023; 25:6684-6692. [PMID: 36806473 DOI: 10.1039/d3cp00004d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have combined the extended X-ray absorption fine structure (EXAFS) and X-ray emission spectroscopy (XES) to investigate the local structure and the local iron magnetic moments of (Li1-xFex)OHFeSe (x∼0.2) superconductors. The local structure, studied by Fe K-edge EXAFS measurements, is found to be inhomogeneous that is characterized by different Fe-Se bond lengths. The inhomogeneous phase exhibits a peculiar temperature dependence with lattice anomalies in the local structural parameters at the critical temperature Tc (36 K) and at the spin density wave (SDW) transition temperature TN (130 K). Fe Kβ XES shows iron to be in a low spin state with the local Fe magnetic moment evolving anomalously as a function of temperature. Apart from a quantitative measurement of the local structure of (Li1-xFex)OHFeSe, providing direct evidence of nanoscale inhomogeneity, the results provide further evidence of the vital role that the coupled electronic, lattice and magnetic degrees of freedom play in the iron-based superconductors.
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Affiliation(s)
- G Tomassucci
- Dipartimento di Fisica, Universitá di Roma "La Sapienza" - P. le Aldo Moro 2, 00185 Roma, Italy.
| | - L Tortora
- Dipartimento di Fisica, Universitá di Roma "La Sapienza" - P. le Aldo Moro 2, 00185 Roma, Italy.
| | - G M Pugliese
- Dipartimento di Fisica, Universitá di Roma "La Sapienza" - P. le Aldo Moro 2, 00185 Roma, Italy.
| | - F Stramaglia
- Dipartimento di Fisica, Universitá di Roma "La Sapienza" - P. le Aldo Moro 2, 00185 Roma, Italy. .,Microscopy and Magnetism Group, Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - L Simonelli
- CELLS - ALBA Synchrotron Radiation Facility, Carrer de la Llum 2-26, 08290, Cerdanyola del Valles, Barcelona, Spain
| | - C Marini
- CELLS - ALBA Synchrotron Radiation Facility, Carrer de la Llum 2-26, 08290, Cerdanyola del Valles, Barcelona, Spain
| | - K Terashima
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama 700-8530, Japan.,National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047, Japan
| | - T Wakita
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama 700-8530, Japan
| | - S Ayukawa
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama 700-8530, Japan
| | - T Yokoya
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama 700-8530, Japan
| | - K Kudo
- Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - M Nohara
- Department of Quantum Matter, Hiroshima University, Hiroshima 739-8530, Japan
| | - T Mizokawa
- Department of Applied Physics, Waseda University, Tokyo 169-8555, Japan
| | - N L Saini
- Dipartimento di Fisica, Universitá di Roma "La Sapienza" - P. le Aldo Moro 2, 00185 Roma, Italy.
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Pugliese GM, Paris E, Capone FG, Stramaglia F, Wakita T, Terashima K, Yokoya T, Mizokawa T, Mizuguchi Y, Saini NL. The local structure of self-doped BiS 2-based layered systems as a function of temperature. Phys Chem Chem Phys 2020; 22:22217-22225. [PMID: 32996510 DOI: 10.1039/d0cp03974h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have studied the local structure of layered Eu(La,Ce)FBiS2 compounds by Bi L3-edge extended X-ray absorption fine structure (EXAFS) measurements as a function of temperature. We find that the BiS2 sub-lattice is largely distorted in EuFBiS2, characterized by two different in-plane Bi-S1 distances. The distortion is marginally affected by partial substitutions of Ce (Eu0.5Ce0.5FBiS2) and La (Eu0.5La0.5FBiS2). The temperature dependence of the local structure distortion reveals an indication of possible charge density wave like instability in the pristine self-doped EuFBiS2 and Ce substituted Eu0.5Ce0.5FBiS2 while it is suppressed in La substituted Eu0.5La0.5FBiS2. In compounds with higher superconducting transition temperature, the axial Bi-S2 bond distance is elongated and the related bond stiffness decreased, suggesting some important role of this in the charge transfer mechanism for self-doping in the active BiS2-layer. In-plane Bi-S1 distances are generally softer than the axial Bi-S2 distance and they suffer further softening by the substitutions. The results are discussed in relation to an important role of the Bi defect chemistry driven asymmetric local environment in the physical properties of these materials.
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Affiliation(s)
- G M Pugliese
- Dipartimento di Fisica, Universitá di Roma "La Sapienza"- P. le Aldo Moro 2, 00185 Roma, Italy.
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Abstract
Mutations in the cardiac sodium channel SCN5A can cause phenotypic overlap syndrome of long QT syndrome and Brugada syndrome. However, Brugada-type ST elevations in patients with overlap syndrome are often concealed, which creates a diagnostic challenge. A 38-year-old man was admitted due to ventricular fibrillation (VF). The 12-lead electrocardiogram showed a prolonged QT interval and saddleback-type ST elevation. Pilsicainide administration induced coved-type ST elevation and VF triggered by a single premature ventricular contraction. A genetic analysis showed an SCN5A c.5350G>A p.E1784K mutation. The present case suggests the importance of a drug administration test being performed in the clinical management of overlap syndrome.
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Affiliation(s)
- Hideyuki Hasebe
- Division of Arrhythmology, Shizuoka Saiseikai General Hospital, Japan
- Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Japan
| | - Tomoyo Yokoya
- Division of Arrhythmology, Shizuoka Saiseikai General Hospital, Japan
| | - Nobuyuki Murakoshi
- Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Japan
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Pugliese GM, Stramaglia F, Goto Y, Terashima K, Simonelli L, Fujiwara H, Puri A, Marini C, Hacisalihoglu MY, d'Acapito F, Yokoya T, Mizokawa T, Mizuguchi Y, Saini NL. Temperature dependent local atomic displacements in NaSn 2As 2 system. J Phys Condens Matter 2019; 31:425402. [PMID: 31226700 DOI: 10.1088/1361-648x/ab2bd4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
NaSn2As2 is mechanically exfoliable layered van der Waals (vdW) Zintl phase that is getting interesting due to its low thermal conductivity and recently observed superconductivity. Here, we have investigated the temperature dependent local structure of NaSn2As2 by a combined analysis of As K-edge and Sn K-edge extended x-ray absorption fine structure measurements. The system is intrinsically disordered with the interatomic distances largely consistent to those estimated by average structure measurements. The stretching force constants of different bond distances have been determined using temperature dependent mean square relative displacements. The Sn-As distance is the strongest bond in this system, having covalent nature, unlike the weaker interlayer distances which are characterized by vdW type bonding. Among them, As-Na distance is slightly weaker than Sn-Sn(i) below ∼200 K and tends to get stronger above this temperature. The anomalous behavior of As-Na bond suggests that the mechanical exfoliation in this system is likely to be temperature dependent. The anomaly in the interlayer atomic correlations may be due to a charge density wave-like instability around this temperature, indicated by earlier experiments. The local structure and disorder are discussed in relation to the physical properties of NaSn2As2.
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Affiliation(s)
- G M Pugliese
- Dipartimento di Fisica, Università di Roma 'La Sapienza', P. le Aldo Moro 2, 00185 Roma, Italy
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5
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Yokoya T, Terashima K, Takeda A, Fukura T, Fujiwara H, Muro T, Kinoshita T, Kato H, Yamasaki S, Oguchi T, Wakita T, Muraoka Y, Matsushita T. Asymmetric Phosphorus Incorporation in Homoepitaxial P-Doped (111) Diamond Revealed by Photoelectron Holography. Nano Lett 2019; 19:5915-5919. [PMID: 31373825 DOI: 10.1021/acs.nanolett.9b01481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
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.
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Affiliation(s)
- T Yokoya
- Research Institute for Interdisciplinary Science (RIIS) , Okayama University , Okayama 700-8530 , Japan
- Graduate School of Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - K Terashima
- Research Institute for Interdisciplinary Science (RIIS) , Okayama University , Okayama 700-8530 , Japan
| | - A Takeda
- Graduate School of Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - T Fukura
- Graduate School of Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - H Fujiwara
- Graduate School of Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - T Muro
- Japan Synchrotron Radiation Research Institute (JASRI) , 1-1-1 Kouto, Sayo , Hyogo 679-5198 , Japan
| | - T Kinoshita
- Japan Synchrotron Radiation Research Institute (JASRI) , 1-1-1 Kouto, Sayo , Hyogo 679-5198 , Japan
| | - H Kato
- Advanced Power Electronics Research Center , National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba Center 2, Tsukuba , Ibaraki 305-8568 , Japan
| | - S Yamasaki
- Advanced Power Electronics Research Center , National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba Center 2, Tsukuba , Ibaraki 305-8568 , Japan
| | - T Oguchi
- Institute of Scientific and Industrial Research , Osaka University , 8-1 Mihogaoka, Ibaraki , Osaka 567-0047 , Japan
| | - T Wakita
- Research Institute for Interdisciplinary Science (RIIS) , Okayama University , Okayama 700-8530 , Japan
| | - Y Muraoka
- Research Institute for Interdisciplinary Science (RIIS) , Okayama University , Okayama 700-8530 , Japan
- Graduate School of Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - T Matsushita
- Japan Synchrotron Radiation Research Institute (JASRI) , 1-1-1 Kouto, Sayo , Hyogo 679-5198 , Japan
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Paris E, Mizuguchi Y, Wakita T, Terashima K, Yokoya T, Mizokawa T, Saini NL. Suppression of structural instability in LaOBiS 2-x Se x by Se substitution. J Phys Condens Matter 2018; 30:455703. [PMID: 30265246 DOI: 10.1088/1361-648x/aae501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Isovalent substitution of S by Se in LaOBiS2-x Se x has a substantial effect on its electronic structure and thermoelectric properties. To investigate the possible role of BiS2 structural instability, we have studied the local structure of LaOBiS2-x Se x ([Formula: see text]) using temperature dependent Bi L3-edge extended x-ray absorption fine structure measurements. The results reveal that the local structure of the two compounds is significantly different. The BiS2 sub-lattice is largely distorted in LaOBiS2 (x = 0.0), with two in-plane Bi-S1 distances separated by ∼0.4 Å instead LaOBiSSe (x = 1.0) showing much smaller local disorder with two in-plane Bi-Se distances in the plane being separated by ∼0.2 Å. Temperature dependent study shows that the two Bi-S1 distances are characterized by different bond strength in LaOBiS2 (x = 0.0) while it is similar for the Bi-Se distances in LaOBiSSe (x = 1.0). The out of plane Bi-S2 bond is harder in LaOBiSSe indicating that the structural instability of BiS2 layer has large effect on the out-of-plane atomic correlations. The results suggest that the local structure of LaOBiS2-x Se x is an important factor to describe differing electronic and thermal transport of the two compounds.
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Affiliation(s)
- E Paris
- Dipartimento di Fisica, Università di Roma 'La Sapienza', P. le Aldo Moro 2, 00185 Roma, Italy
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Sugimoto T, Paris E, Wakita T, Terashima K, Yokoya T, Barinov A, Kajitani J, Higashinaka R, Matsuda TD, Aoki Y, Mizokawa T, Saini NL. Metallic phase in stoichiometric CeOBiS 2 revealed by space-resolved ARPES. Sci Rep 2018; 8:2011. [PMID: 29386537 PMCID: PMC5792495 DOI: 10.1038/s41598-018-20351-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 01/16/2018] [Indexed: 11/29/2022] Open
Abstract
Recently CeOBiS2 system without any fluorine doping is found to show superconductivity posing question on its origin. Using space resolved ARPES we have found a metallic phase embedded in the morphological defects and at the sample edges of stoichiometric CeOBiS2. While bulk of the sample is semiconducting, the embedded metallic phase is characterized by the usual electron pocket at X point, similar to the Fermi surface of doped BiS2-based superconductors. Typical size of the observed metallic domain is larger than the superconducting correlation length of the system suggesting that the observed superconductivity in undoped CeOBiS2 might be due to this embedded metallic phase at the defects. The results also suggest a possible way to develop new systems by manipulation of the defects in these chalcogenides with structural instability.
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Affiliation(s)
- T Sugimoto
- Dipartimento di Fisica, Universitá di Roma "La Sapienza" - Piazzale Aldo Moro 2, 00185, Roma, Italy.,Department of Complexity Science and Engineering, University of Tokyo, 5-1-5 Kashiwanoha, Chiba, 277-8561, Japan.,Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Chiba, 277-8561, Japan
| | - E Paris
- Dipartimento di Fisica, Universitá di Roma "La Sapienza" - Piazzale Aldo Moro 2, 00185, Roma, Italy
| | - T Wakita
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama, 700-8530, Japan
| | - K Terashima
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama, 700-8530, Japan
| | - T Yokoya
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama, 700-8530, Japan
| | - A Barinov
- Elettra, Sincrotrone Trieste, Strada Statale 14, Km 163.5, Basovizza, 34149, Trieste, Italy
| | - J Kajitani
- Department of Physics, Tokyo Metropolitan University, Hachioji, 192-0397, Japan
| | - R Higashinaka
- Department of Physics, Tokyo Metropolitan University, Hachioji, 192-0397, Japan
| | - T D Matsuda
- Department of Physics, Tokyo Metropolitan University, Hachioji, 192-0397, Japan
| | - Y Aoki
- Department of Physics, Tokyo Metropolitan University, Hachioji, 192-0397, Japan
| | - T Mizokawa
- Department of Applied Physics, Waseda University, Tokyo, 169-8555, Japan
| | - N L Saini
- Dipartimento di Fisica, Universitá di Roma "La Sapienza" - Piazzale Aldo Moro 2, 00185, Roma, Italy.
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8
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Wakita T, Okazaki H, Jabuchi T, Hamada H, Muraoka Y, Yokoya T. Electronic structure of K-doped picene film on HOPG. J Phys Condens Matter 2017; 29:064001. [PMID: 28002037 DOI: 10.1088/1361-648x/29/6/064001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have performed potassium (K)-doping dependent photoemission (PES) measurements of picene film on highly oriented pyrolytic graphite (HOPG). K-doping dependent valence band PES data exhibits a shift of the valence band to a higher binding energy, indicative of the charge transfer from the K atoms to the picene film. K-doping dependent PES spectra near the Fermi level (E F) show the appearance and disappearance of a Fermi edge, indicating the metallic properties of the film at certain K concentrations. High-resolution PES spectrum at the lowest measured temperature does not show an opening of the superconducting gap, requesting further studies to explore the superconducting properties of the K-doped picene film. The results will be discussed by comparison with previous and recent spectroscopic studies.
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Affiliation(s)
- T Wakita
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
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9
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Denholme SJ, Okazaki H, Demura S, Deguchi K, Fujioka M, Yamaguchi T, Takeya H, ElMassalami M, Fujiwara H, Wakita T, Yokoya T, Takano Y. Pressure-dependent magnetization and magnetoresistivity studies on tetragonal FeS (mackinawite): revealing its intrinsic metallic character. Sci Technol Adv Mater 2014; 15:055007. [PMID: 27877719 PMCID: PMC5099680 DOI: 10.1088/1468-6996/15/5/055007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/07/2014] [Indexed: 06/05/2023]
Abstract
The transport and magnetic properties of the tetragonal Fe[Formula: see text]S were investigated using magnetoresistivity and magnetization within [Formula: see text] K, [Formula: see text] 70 kOe and [Formula: see text] 3.0 GPa. In addition, room-temperature x-ray diffraction and photoelectron spectroscopy were also applied. In contrast to previously reported nonmetallic character, Fe[Formula: see text]S is intrinsically metallic but due to a presence of a weak localization such metallic character is not exhibited below room temperature. An applied pressure reduces strongly this additional resistive contribution and as such enhances the temperature range of the metallic character which, for ∼3 GPa, is evident down to 75 K. The absence of superconductivity as well as the mechanism behind the weak localization will be discussed.
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Affiliation(s)
- S J Denholme
- National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, 305-0047, Japan
| | - H Okazaki
- National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, 305-0047, Japan
| | - S Demura
- National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, 305-0047, Japan
| | - K Deguchi
- National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, 305-0047, Japan
| | - M Fujioka
- National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, 305-0047, Japan
| | - T Yamaguchi
- National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, 305-0047, Japan
| | - H Takeya
- National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, 305-0047, Japan
| | - M ElMassalami
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro RJ, Brazil
| | - H Fujiwara
- Research Laboratory for Surface Science, Okayama University, Okayama, 700-8530, Japan
| | - T Wakita
- Research Laboratory for Surface Science, Okayama University, Okayama, 700-8530, Japan
| | - T Yokoya
- Research Laboratory for Surface Science, Okayama University, Okayama, 700-8530, Japan
| | - Y Takano
- National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, 305-0047, Japan
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Rayjada PA, Chainani A, Matsunami M, Taguchi M, Tsuda S, Yokoya T, Shin S, Sugawara H, Sato H. Kondo scaling of the pseudogap in CeOs4Sb12 and CeFe4P12. J Phys Condens Matter 2010; 22:095502. [PMID: 21389417 DOI: 10.1088/0953-8984/22/9/095502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
CeOs(4)Sb(12) and CeFe(4)P(12) are classified as Kondo semiconductors, which show coupled changes in electrical transport, thermodynamic and magnetic properties with a low-temperature semiconductor-like electrical resistivity. We have carried out core level and valence band photoemission spectroscopy on single crystal CeOs(4)Sb(12) and CeFe(4)P(12) to study their electronic structure and the evolution of states at the Fermi level as a function of temperature (∼10-300 K). The Ce 3d core level spectra show the presence of f(0), f(1) and f(2) final states with very different relative intensities in the two compounds. Single-impurity Anderson model calculations provide f electron counts of n(f) = 0.97 and 0.86 per Ce atom, suggestive of a low- and high-T(K) (= single ion Kondo temperature) for CeOs(4)Sb(12) and CeFe(4)P(12), respectively. The high-resolution temperature-dependent near-Fermi level spectra show pseudogaps of energy ∼ 50 meV and ∼ 110 meV in the valence band density of states (DOS) of CeOs(4)Sb(12) and CeFe(4)P(12), respectively. The temperature dependence of the DOS at the Fermi level follows the change in effective magnetic moment estimated from magnetic susceptibility for both materials, confirming the Kondo nature of the pseudogap in CeOs(4)Sb(12) and CeFe(4)P(12). A compilation of measured pseudogaps using photoemission and optical spectroscopy identifies the charge gaps Δ(C) for Ce-based Kondo semiconductors and provides a direct relation with T(K) given by Δ(C) ∼ 2k(B)T(K). In conjunction with the known behaviour of the spin gaps Δ(S) ∼ k(B)T(K), the results establish the coupled energy scaling of the spin and charge gaps in Kondo semiconductors.
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Affiliation(s)
- P A Rayjada
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
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11
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Ishizaka K, Eguchi R, Tsuda S, Chainani A, Yokoya T, Kiss T, Shimojima T, Togashi T, Watanabe S, Chen CT, Takano Y, Nagao M, Sakaguchi I, Takenouchi T, Kawarada H, Shin S. Temperature-dependent localized excitations of doped carriers in superconducting diamond. Phys Rev Lett 2008; 100:166402. [PMID: 18518227 DOI: 10.1103/physrevlett.100.166402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Indexed: 05/26/2023]
Abstract
Laser-excited photoemission spectroscopy is used to show that the doped carriers in metallic or superconducting diamond couple strongly to the lattice via high-energy (approximately 150 meV) optical phonons, with direct observations of localized Franck-Condon multiphonon sidebands appearing as Fermi-edge replicas. It exhibits a temperature-dependent spectral weight transfer from higher to lower energy sidebands and zero-phonon Fermi-edge states. The quantified coupling strength shows a systematic increase on lowering temperature, implicating its relation to the normal state transport and superconductivity.
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Affiliation(s)
- K Ishizaka
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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12
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Baba T, Yokoya T, Tsuda S, Kiss T, Shimojima T, Ishizaka K, Takeya H, Hirata K, Watanabe T, Nohara M, Takagi H, Nakai N, Machida K, Togashi T, Watanabe S, Wang XY, Chen CT, Shin S. Bulk electronic structure of the antiferromagnetic superconducting phase in ErNi2B2C. Phys Rev Lett 2008; 100:017003. [PMID: 18232808 DOI: 10.1103/physrevlett.100.017003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Indexed: 05/25/2023]
Abstract
We have performed temperature- (T-)dependent laser-photoemission spectroscopy of the antiferromagnetic (AF) superconductor ErNi2B2C to study the electronic-structure evolution reflecting the interplay between antiferromagnetism and superconductivity. The spectra at the superconducting (SC) phase show a very broad spectral shape. A T-dependent SC gap shows a sudden deviation from the BCS prediction just below TN. This observation can be explained well by the theoretical model and thus represents the characteristic bulk electronic structure of the AF SC phase for the first time.
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Affiliation(s)
- T Baba
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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13
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Shimojima T, Shibata Y, Ishizaka K, Kiss T, Chainani A, Yokoya T, Togashi T, Wang XY, Chen CT, Watanabe S, Yamaura J, Yonezawa S, Muraoka Y, Hiroi Z, Saitoh T, Shin S. Interplay of superconductivity and rattling phenomena in beta-pyrochlore KOs2O6 studied by photoemission spectroscopy. Phys Rev Lett 2007; 99:117003. [PMID: 17930463 DOI: 10.1103/physrevlett.99.117003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Indexed: 05/25/2023]
Abstract
The electronic structure near the Fermi level (EF) of the beta-pyrochlore superconductor KOs2O6 is studied using laser-excited ultrahigh-resolution photoemission spectroscopy. The superconducting gap clearly opens across the superconducting transition (Tc=9.6 K), with the strong electron-phonon coupling value of 2Delta(0)/k B Tc>or=4.56. A fitting analysis identifies clear anomalies at Tp=7.5 K in the temperature dependencies of the superconducting gap size and the quasiparticle relaxation lifetime. These anomalies and the fine spectral structures arising from phonons suggest that the existence of the rattling behavior of K ions significantly affects the superconductivity in KOs2O6.
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Affiliation(s)
- T Shimojima
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
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Ishizaka K, Eguchi R, Tsuda S, Yokoya T, Chainani A, Kiss T, Shimojima T, Togashi T, Watanabe S, Chen CT, Zhang CQ, Takano Y, Nagao M, Sakaguchi I, Takenouchi T, Kawarada H, Shin S. Observation of a superconducting gap in boron-doped diamond by laser-excited photoemission spectroscopy. Phys Rev Lett 2007; 98:047003. [PMID: 17358800 DOI: 10.1103/physrevlett.98.047003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Indexed: 05/14/2023]
Abstract
We investigate the temperature (T)-dependent low-energy electronic structure of a boron-doped diamond thin film using ultrahigh resolution laser-excited photoemission spectroscopy. We observe a clear shift of the leading edge below T=11 K, indicative of a superconducting gap opening (Delta approximately 0.78 meV at T=4.5 K). The gap feature is significantly broad and a well-defined quasiparticle peak is lacking even at the lowest temperature of measurement (=4.5 K). We discuss our results in terms of disorder effects on the normal state transport and superconductivity in this system.
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Affiliation(s)
- K Ishizaka
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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15
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Shimojima T, Ishizaka K, Tsuda S, Kiss T, Yokoya T, Chainani A, Shin S, Badica P, Yamada K, Togano K. Angle-resolved photoemission study of the cobalt oxide superconductor Na(x)CoO(2) x yH(2)O: observation of the Fermi surface. Phys Rev Lett 2006; 97:267003. [PMID: 17280457 DOI: 10.1103/physrevlett.97.267003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Indexed: 05/13/2023]
Abstract
The cobalt oxide superconductor Na(x)CoO(2) x yH(2)O is studied by angle-resolved photoemission spectroscopy. We report the Fermi surface (FS) topology and electronic structure near the Fermi level (E(F)) in the normal state of Na(x)CoO(2) x yH(2)O. Our result indicates the presence of the hexagonal FS centered at the Gamma point, while the small pocket FSs along Gamma-K direction are absent, similar to Na(x)CoO(2). The top of the e(g)(') band, which is expected in band calculations to form the small pocket FSs, extends to within approximately 30 meV below E(F), closer to E(F) than in Na(x)CoO(2). We discuss its possible role in superconductivity, comparing with other experimental and theoretical results.
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Affiliation(s)
- T Shimojima
- Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
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Eguchi R, Kiss T, Tsuda S, Shimojima T, Mizokami T, Yokoya T, Chainani A, Shin S, Inoue IH, Togashi T, Watanabe S, Zhang CQ, Chen CT, Arita M, Shimada K, Namatame H, Taniguchi M. Bulk- and surface-sensitive high-resolution photoemission study of two mott-hubbard systems: SrVO3 and CaVO3. Phys Rev Lett 2006; 96:076402. [PMID: 16606115 DOI: 10.1103/physrevlett.96.076402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Indexed: 05/08/2023]
Abstract
We study the electronic structure of Mott-Hubbard systems SrVO3 and CaVO3 with bulk and surface-sensitive high-resolution photoemission spectroscopy, using a vacuum ultraviolet laser, synchrotron radiation, and a discharge lamp (hv = 7-21 eV). A systematic suppression of the density of states (DOS) within approximately 0.2 eV of the Fermi level (EF) is found on decreasing photon energy, i.e., on increasing bulk sensitivity. The coherent band in SrVO3 and CaVO3 is shown to consist of surface and bulk-derived features, separated in energy. The stronger distortion on surface of CaVO3 compared to SrVO3 leads to a higher surface metallicity in the coherent DOS at EF, consistent with recent theory.
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Affiliation(s)
- R Eguchi
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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17
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Ito T, Chainani A, Haruna T, Kanai K, Yokoya T, Shin S, Kato R. Temperature-dependent Luttinger surfaces. Phys Rev Lett 2005; 95:246402. [PMID: 16384402 DOI: 10.1103/physrevlett.95.246402] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Indexed: 05/05/2023]
Abstract
The Luttinger surface of an organic metal (TTF-TCNQ), possessing charge order and spin-charge separated band dispersions, is investigated using temperature-dependent angle-resolved photoemission spectroscopy. The Luttinger surface topology, obtained from momentum distribution curves, changes from quasi-2D (dimensional) to quasi-1D with temperature. The high temperature quasi-2D surface exhibits 4kF charge-density-wave (CDW) superstructure in the TCNQ derived holon band, in the absence of 2kF order. Decreasing temperature results in quasi-1D nested 2kF CDW order in the TCNQ spinon band and in the TTF surface. The results establish the link in momentum space between charge order and spin-charge separation in a Luttinger liquid.
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Affiliation(s)
- T Ito
- The Institute of Physical and Chemical Research (RIKEN), Sayo-gun, Hyogo 679-5143, Japan.
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18
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Yokoya T, Nakamura T, Matsushita T, Muro T, Takano Y, Nagao M, Takenouchi T, Kawarada H, Oguchi T. Origin of the metallic properties of heavily boron-doped superconducting diamond. Nature 2005; 438:647-50. [PMID: 16319887 DOI: 10.1038/nature04278] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Accepted: 09/29/2005] [Indexed: 11/09/2022]
Abstract
The physical properties of lightly doped semiconductors are well described by electronic band-structure calculations and impurity energy levels. Such properties form the basis of present-day semiconductor technology. If the doping concentration n exceeds a critical value n(c), the system passes through an insulator-to-metal transition and exhibits metallic behaviour; this is widely accepted to occur as a consequence of the impurity levels merging to form energy bands. However, the electronic structure of semiconductors doped beyond n(c) have not been explored in detail. Therefore, the recent observation of superconductivity emerging near the insulator-to-metal transition in heavily boron-doped diamond has stimulated a discussion on the fundamental origin of the metallic states responsible for the superconductivity. Two approaches have been adopted for describing this metallic state: the introduction of charge carriers into either the impurity bands or the intrinsic diamond bands. Here we show experimentally that the doping-dependent occupied electronic structures are consistent with the diamond bands, indicating that holes in the diamond bands play an essential part in determining the metallic nature of the heavily boron-doped diamond superconductor. This supports the diamond band approach and related predictions, including the possibility of achieving dopant-induced superconductivity in silicon and germanium. It should also provide a foundation for the possible development of diamond-based devices.
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Affiliation(s)
- T Yokoya
- Japan Synchrotron Radiation Research Institute (JASRI)/SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan.
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Taguchi M, Chainani A, Horiba K, Takata Y, Yabashi M, Tamasaku K, Nishino Y, Miwa D, Ishikawa T, Takeuchi T, Yamamoto K, Matsunami M, Shin S, Yokoya T, Ikenaga E, Kobayashi K, Mochiku T, Hirata K, Hori J, Ishii K, Nakamura F, Suzuki T. Evidence for suppressed screening on the surface of high temperature La(2-x)SrxCuO4 and Nd2(2-x)CexCuO4 superconductors. Phys Rev Lett 2005; 95:177002. [PMID: 16383858 DOI: 10.1103/physrevlett.95.177002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Indexed: 05/05/2023]
Abstract
Hard x-ray photoemission spectroscopy (PES) of Cu core electronic states, with a probing depth of approximately 60 A, is used to show that the Zhang-Rice singlet feature is present in La2CuO4 but is absent in Nd2CuO4. Hole and electron doping in La(2-x)SrxCuO4 (LSCO) and Nd(2-x)CexCuO4 (NCCO) result in new well-screened features which are missing in soft x-ray PES. Impurity Anderson model calculations establish screening from doped states as its origin, which is strongly suppressed within 15 A of the surface. Complemented with x-ray absorption spectroscopy, the small chemical-potential shift in core levels (approximately 0.2 eV) are shown to be consistent with modifications of valence and conduction band states spanning the band gap (approximately 1 eV) upon hole and electron doping in LSCO and NCCO.
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Affiliation(s)
- M Taguchi
- Soft X-ray Spectroscopy Laboratory, RIKEN/SPring-8, Mikazuki, Hyogo 679-5148, Japan
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20
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Kiss T, Kanetaka F, Yokoya T, Shimojima T, Kanai K, Shin S, Onuki Y, Togashi T, Zhang C, Chen CT, Watanabe S. Photoemission spectroscopic evidence of gap anisotropy in an f-electron superconductor. Phys Rev Lett 2005; 94:057001. [PMID: 15783678 DOI: 10.1103/physrevlett.94.057001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2004] [Indexed: 05/24/2023]
Abstract
We used low-temperature ultrahigh-resolution (360 microeV) photoemission spectroscopy with a laser as a photon source (Laser-PES) to study the superconducting (SC) gap of an f-electron superconductor CeRu2. The unique combination of the large escape depth expected from the known universal behavior and extremely high-energy resolution has enabled us to directly measure the bulk SC gap of an f-electron superconductor for the first time. The present study provides direct evidence for an anisotropic SC gap in CeRu2, and also demonstrates the potential of Laser-PES in investigating unconventional superconductivity realized in correlated d- and f-electron superconductors.
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Affiliation(s)
- T Kiss
- Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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Tamura R, Takeuchi T, Aoki C, Takeuchi S, Kiss T, Yokoya T, Shin S. Experimental evidence for the p-d hybridization in the Cd-Ca quasicrystal: origin of the pseudogap. Phys Rev Lett 2004; 92:146402. [PMID: 15089561 DOI: 10.1103/physrevlett.92.146402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Indexed: 05/24/2023]
Abstract
Ca 2p-3d resonant photoemission spectroscopy of a Cd6Ca crystalline approximant unambiguously demonstrates that the low-lying unoccupied 3d levels of calcium are lowered below the Fermi energy by the formation of the approximant, as suggested from electronic structure calculations [Phys. Rev. Lett. 87, 206408 (2001)]]. Moreover, the Ca 3d partial density of states (DOS) obtained near the Fermi energy is in reasonable agreement with theoretical Ca 3d DOS. These results verify the unconventional picture that the origin of the pseudogap in the Cd-based quasicrystals is due to hybridization of the Ca 3d band with the Cd 5p band.
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Affiliation(s)
- R Tamura
- Department of Materials Science and Technology, Tokyo University of Science, Noda, Chiba 278-8510, Japan
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22
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Tsuda S, Yokoya T, Takano Y, Kito H, Matsushita A, Yin F, Itoh J, Harima H, Shin S. Definitive experimental evidence for two-band superconductivity in MgB2. Phys Rev Lett 2003; 91:127001. [PMID: 14525389 DOI: 10.1103/physrevlett.91.127001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2003] [Indexed: 05/24/2023]
Abstract
The superconducting-gap of MgB2 has been studied by high-resolution angle-resolved photoemission spectroscopy. The results show that superconducting gaps with values of 5.5 and 2.2 meV open on the sigma band and the pi band, respectively, but both the gaps close at the bulk transition temperature, providing a definitive experimental evidence for the two-band superconductivity with strong interband pairing interaction in MgB2. The experiments validate the role of k-dependent electron-phonon coupling as the origin of multiple-gap superconductivity as well as the high transition temperature of MgB2.
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Affiliation(s)
- S Tsuda
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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23
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Abstract
High-resolution angle-resolved photoemission spectroscopy was used to study the superconducting energy gap and changes in the spectral function across the superconducting transition in the quasi-two-dimensional superconductor 2H-NbSe2. The momentum dependence of the superconducting gap was determined on different Fermi surface sheets. The results indicate Fermi surface sheet-dependent superconductivity in this low-transition temperature multiband system and provide a description consistent with thermodynamic measurements and the anomalous de Haas-van Alphen oscillations observed in the superconducting phase. The present data suggest the importance of Fermi surface sheet-dependent superconductivity in explaining exotic superconductivity in other multiband systems with complex Fermi surface topology, such as the borides and f-electron superconductors.
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Affiliation(s)
- T Yokoya
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
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24
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Tsuda S, Yokoya T, Kiss T, Takano Y, Togano K, Kito H, Ihara H, Shin S. Evidence for a multiple superconducting gap in MgB(2) from high-resolution photoemission spectroscopy. Phys Rev Lett 2001; 87:177006. [PMID: 11690299 DOI: 10.1103/physrevlett.87.177006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2001] [Indexed: 05/23/2023]
Abstract
We study the new binary intermetallic superconductor MgB(2) using high-resolution photoemission spectroscopy. The superconducting-state spectrum measured at 5.4 K shows a coherent peak with a shoulder structure, in sharp contrast to that expected from a simple isotropic-gap opening. The spectrum can be well reproduced using the weighted sum of two Dynes functions with the gap sizes of 1.7 and 5.6 meV. Temperature-dependent study shows that both gaps close at the bulk transition temperature. These results provide spectroscopic evidence for a multiple gap of MgB(2).
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Affiliation(s)
- S Tsuda
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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25
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Yokoya T, Kiss T, Watanabe T, Shin S, Nohara M, Takagi H, Oguchi T. Ultrahigh-resolution photoemission spectroscopy of Ni borocarbides: direct observation of the superconducting gap and a change in gap anisotropy by impurity. Phys Rev Lett 2000; 85:4952-4955. [PMID: 11102159 DOI: 10.1103/physrevlett.85.4952] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2000] [Indexed: 05/23/2023]
Abstract
We have performed ultrahigh-resolution photoemission spectroscopy of Y(Ni1-xPtx)2B2C ( x = 0.0 and 0.2) in order to study the changes in the density of states across the superconducting transition. Because of a drastic increase in energy resolution, we clearly observe the opening of superconducting gaps across T(c) in both compounds. Furthermore, we find a small but significant difference in the superconducting-state spectral shape. This can be explained in terms of reduction in gap anisotropy by introducing impurities and provides spectroscopic evidence for an anisotropic s-wave gap in YNi2B2C.
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Affiliation(s)
- T Yokoya
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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26
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Chainani A, Yokoya T, Kiss T, Shin S. Photoemission spectroscopy of the strong-coupling superconducting transitions in lead and niobium. Phys Rev Lett 2000; 85:1966-1969. [PMID: 10970659 DOI: 10.1103/physrevlett.85.1966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2000] [Indexed: 05/23/2023]
Abstract
We study the changes in the electronic structure associated with low- T(c) strong-coupling superconducting transitions in Pb and Nb using ultrahigh-resolution (2.3 meV) temperature-dependent (5.3-12.0 K) photoemission spectroscopy. We observe peaks in the density of states on entering the superconducting-phase accompanying gap formation and spectacular redistribution of spectral weight at low energy scales as a function of temperature. The well-known peak-dip feature of the high- T(c) cuprates is seen in Pb, making it a characteristic of strong-coupling superconductivity.
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Affiliation(s)
- A Chainani
- Institute for Plasma Research, Bhat, Gandhinagar-382 428, India and Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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Okamoto-Mizuno K, Yokoya T, Kudoh Y. Effects of activity of daily living and gender on circadian rhythms of the elderly in a nursing home. J Physiol Anthropol Appl Human Sci 2000; 19:53-7. [PMID: 10979250 DOI: 10.2114/jpa.19.53] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The objective of this study was to confirm the effects of ADL (Activity of Daily Living) and gender on circadian rhythms of the elderly in a nursing home. Twenty-one elderly volunteers, aged over 65 years, were divided in four groups depending on their ADL and gender: subjects with almost no problem in ADL (H males, H females) and those who were almost bedridden (L males, L females). Oral temperature, heart rate, blood pressure, time of sleep and wake, subjective sleepiness, overall feeling and vitality were measured every 4 hours during the day continuously for six days. The circadian rhythm was calculated by using the least squares fit of cosine function. Subjective sleep quality was also surveyed. In the sleep/wake rhythm, the mesor was significantly higher in L males compared to the other groups and the amplitude was significantly lower in L females compared to other groups. The subjective sleepiness was higher in L males compared to the other groups and L females showed a higher sleepiness compared to H females. No significant difference among the group was observed in subjective sleep quality. In conclusion, these results indicate that the subjective sleepiness and sleep/wake rhythm differ depending on ADL and gender, although no significant difference was observed in physiological parameters. ADL and gender based difference in subjective sleepiness and sleep/wake rhythm should be taken into account with regard to the care of the elderly in nursing homes.
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Abstract
Bedroom and bed climate of the elderly in a nursing home were surveyed. Twenty-two elderly subjects were divided into four groups depending on their Activity of Daily Living (ADL) and gender. The four groups were: male and female subjects with almost no problems in daily life and an ADL score higher than 5 [H males, H females] and male and female subjects who normally stayed in bed all day with an ADL score lower than 2 [L males, L females]. The temperature and humidity of the bedroom and bed climate were measured continuously for 24 hours. Bedding and clothing condition, subjective sensational vote and subjective sleep evaluation were surveyed before and after sleep for five days continuously. In the daytime, bedroom and bed climate temperature was significantly lower in H females than in the other groups. At night, no significant effect of gender and ADL was observed in bed climate, which was maintained at 33-35 degrees C, RH50-60% in all the groups. Bedding under the body increased significantly in L males and L females compared with H males and H females. The number of underwear increased significantly in H females. Subjective sleep evaluation was significantly better in H females than the other groups. These results suggest that ADL and gender based differences should be taken into account with regard to the care of the elderly in a nursing home.
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Affiliation(s)
- K Okamoto
- Department of Physiology, Dokkyo University School of Medicine
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29
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Norman MR, Ding H, Randeria M, Campuzano JC, Yokoya T, Takeuchi T, Takahashi T, Mochiku T, Kadowaki K, Guptasarma P, Hinks DG. Destruction of the Fermi surface in underdoped high-Tc superconductors. Nature 1998. [DOI: 10.1038/32366] [Citation(s) in RCA: 893] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yokoya T, Chainani A, Takahashi T, Ding H, Campuzano JC, Katayama-Yoshida H, Kasai M, Tokura Y. Angle-resolved photoemission study of Sr2RuO4. Phys Rev B Condens Matter 1996; 54:13311-13318. [PMID: 9985195 DOI: 10.1103/physrevb.54.13311] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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31
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Ding H, Norman MR, Campuzano JC, Randeria M, Bellman AF, Yokoya T, Takahashi T, Mochiku T, Kadowaki K. Angle-resolved photoemission spectroscopy study of the superconducting gap anisotropy in Bi2Sr2CaCu2O8+x. Phys Rev B Condens Matter 1996; 54:R9678-R9681. [PMID: 9984790 DOI: 10.1103/physrevb.54.r9678] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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32
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Kumigashira H, Yang S, Yokoya T, Chainani A, Takahashi T, Uesawa A, Suzuki T, Sakai O, Kaneta Y. High-resolution angle-resolved photoemission spectroscopy of CeBi. Phys Rev B Condens Matter 1996; 54:9341-9345. [PMID: 9984670 DOI: 10.1103/physrevb.54.9341] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Yokoya T, Takahashi T, Mochiku T, Kadowaki K. High-resolution angle-resolved photoemission spectroscopy of the momentum dependence of the superconducting gap in Bi2Sr2CaCu2O8. Phys Rev B Condens Matter 1996; 53:14055-14057. [PMID: 9983197 DOI: 10.1103/physrevb.53.14055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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34
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Campuzano JC, Ding H, Norman MR, Randeria M, Bellman AF, Yokoya T, Takahashi T, Katayama-Yoshida H, Mochiku T, Kadowaki K. Direct observation of particle-hole mixing in the superconducting state by angle-resolved photoemission. Phys Rev B Condens Matter 1996; 53:R14737-R14740. [PMID: 9983343 DOI: 10.1103/physrevb.53.r14737] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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35
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Yang S, Kumigashira H, Yokoya T, Chainani A, Takahashi T, Takeya H, Kadowaki K. High-resolution photoemission study of CeRu2: The dual character of 4f electrons. Phys Rev B Condens Matter 1996; 53:R11946-R11948. [PMID: 9982894 DOI: 10.1103/physrevb.53.r11946] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Yokoya T, Chainani A, Takahashi T, Katayama-Yoshida H, Kasai M, Tokura Y. Extended Van Hove singularity in a noncuprate layered superconductor Sr2RuO4. Phys Rev Lett 1996; 76:3009-3012. [PMID: 10060847 DOI: 10.1103/physrevlett.76.3009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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37
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Yokoya T, Chainani A, Takahashi T, Katayama-Yoshida H, Kasai M, Tokura Y, Shanthi N, Sarma DD. Evidence for correlation effects in Sr2RuO4 from resonant and x-ray photoemission spectroscopy. Phys Rev B Condens Matter 1996; 53:8151-8154. [PMID: 9982294 DOI: 10.1103/physrevb.53.8151] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ding H, Bellman AF, Campuzano JC, Randeria M, Norman MR, Yokoya T, Takahashi T, Katayama-Yoshida H, Mochiku T, Kadowaki K, Jennings G, Brivio GP. Electronic excitations in Bi2Sr 2CaCu2O8: Fermi surface, dispersion, and absence of bilayer splitting. Phys Rev Lett 1996; 76:1533-1536. [PMID: 10061747 DOI: 10.1103/physrevlett.76.1533] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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39
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Kumigashira H, Chainani A, Yokoya T, Akaki O, Takahashi T, Ito M, Kasaya M, Sakai O. High-energy-resolution photoemission study of CeNiSi2 and CePtSi2. Phys Rev B Condens Matter 1996; 53:2565-2568. [PMID: 9983761 DOI: 10.1103/physrevb.53.2565] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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40
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Takahashi T, Yokoya T, Chainani A, Kumigashira H, Akaki O, Kato R. Cooperative effects of electron correlation and charge ordering on the metal-insulator transition in quasi-one-dimensional deuterated (DMe-DCNQI)2Cu. Phys Rev B Condens Matter 1996; 53:1790-1794. [PMID: 9983638 DOI: 10.1103/physrevb.53.1790] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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41
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Takahashi T, Morimoto T, Yokoya T, Kunii S, Komatsubara T, Sakai O. Crystal-field splitting in CeB6 as observed by high-resolution photoemission. Phys Rev B Condens Matter 1995; 52:9140-9142. [PMID: 9979944 DOI: 10.1103/physrevb.52.9140] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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42
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Tanaka A, Chainani A, Yokoya T, Takahashi T, Miyazaki T, Hasegawa S, Mori T. Electronic structure of the quasi-one-dimensional organic conductors DCNQI (N,N'-dicyanoquinonediimine)-Cu salts. Phys Rev B Condens Matter 1995; 52:7951-7959. [PMID: 9979790 DOI: 10.1103/physrevb.52.7951] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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43
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Chainani A, Yokoya T, Morimoto T, Takahashi T, Todo S. High-resolution photoemission spectroscopy of the Verwey transition in Fe3O4. Phys Rev B Condens Matter 1995; 51:17976-17979. [PMID: 9978834 DOI: 10.1103/physrevb.51.17976] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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44
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Randeria M, Jennings G, Ding H, Campuzano JC, Bellman A, Yokoya T, Takahashi T, Katayama-Yoshida H, Mochiku T, Kadowaki K. Momentum distribution sum rule for angle-resolved photoemission. Phys Rev Lett 1995; 74:4951-4954. [PMID: 10058640 DOI: 10.1103/physrevlett.74.4951] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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45
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Ding H, Campuzano JC, Bellman AF, Yokoya T, Norman MR, Randeria M, Takahashi T, Katayama-Yoshida H, Mochiku T, Kadowaki K, Jennings G. Momentum Dependence of the Superconducting Gap in Bi2Sr2CaCu2O8. Phys Rev Lett 1995; 74:2784-2787. [PMID: 10058017 DOI: 10.1103/physrevlett.74.2784] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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46
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Yokoya T, Takahashi T, Mochiku T, Kadowaki K. Anisotropy of the electronic structure and superconducting gap in Bi2Sr2CaCu2O8. Phys Rev B Condens Matter 1995; 51:3945-3948. [PMID: 9979222 DOI: 10.1103/physrevb.51.3945] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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47
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Yokoya T, Takahashi T, Mochiku T, Kadowaki K. Anomalous band folding due to the BiO superstructure in Bi2Sr2CaCu2O8 studied by angle-resolved photoemission. Phys Rev B Condens Matter 1994; 50:10225-10229. [PMID: 9975104 DOI: 10.1103/physrevb.50.10225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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48
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Chainani A, Yokoya T, Morimoto T, Takahashi T, Yoshii S, Kasaya M. High-resolution temperature-dependent photoemission spectroscopy of FeSi: Evidence for localized states. Phys Rev B Condens Matter 1994; 50:8915-8917. [PMID: 9974926 DOI: 10.1103/physrevb.50.8915] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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49
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Takahashi T, Morimoto T, Yokoya T, Kohgi M, Satoh T. High-energy-resolution photoemission study of single-crystal CeSix (x=1.86 and 1.7): A test of the Kondo model. Phys Rev B Condens Matter 1994; 49:15688-15691. [PMID: 10010700 DOI: 10.1103/physrevb.49.15688] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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50
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Furukawa T, Ohno K, Fukui M, Shimahara M, Yokoya T. [Clinical studies on postexodontic bleeding, 1. (author's transl)]. Nihon Koku Geka Gakkai Zasshi 1974; 20:354-8. [PMID: 4549810 DOI: 10.5794/jjoms.20.354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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