1
|
Abstract
The electrical transport properties of a thin film of the diamondoid adamantane, deposited on an Au/W substrate, were investigated experimentally. The current I, in applied potential V, from the admantane-thiol/metal heterstructure to a wire lead on its surface exhibited non-symmetric (diode-like) characteristics and a signature of resistive switching (RS), an effect that is valuable to non-volatile memory applications. I(V) follows a hysteresis curve that passes twice through [Formula: see text] linearly, indicating RS between two states with significantly different conductances, possibly due to an exotic mechanism.
Collapse
Affiliation(s)
- A Jantayod
- Department of Physics, Faculty of Science, Naresuan University, Phitsanulok, 65000, Thailand
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - D Doonyapisut
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - T Eknapakul
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - M F Smith
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.
| | - W Meevasana
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
- Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
- Thailand Center of Excellence in Physics (ThEP), MHESI, Bangkok, 10400, Thailand
| |
Collapse
|
2
|
Nathabumroong S, Eknapakul T, Jaiban P, Yotburut B, Siriroj S, Saisopa T, Mo SK, Supruangnet R, Nakajima H, Yimnirun R, Maensiri S, Meevasana W. Interplay of negative electronic compressibility and capacitance enhancement in lightly-doped metal oxide Bi 0.95La 0.05FeO 3 by quantum capacitance model. Sci Rep 2020; 10:5153. [PMID: 32198381 PMCID: PMC7083945 DOI: 10.1038/s41598-020-61859-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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: 08/30/2019] [Accepted: 02/24/2020] [Indexed: 12/03/2022] Open
Abstract
Light-sensitive capacitance variation of Bi0.95La0.05FeO3 (BLFO) ceramics has been studied under violet to UV irradiation. The reversible capacitance enhancement up to 21% under 405 nm violet laser irradiation has been observed, suggesting a possible degree of freedom to dynamically control this in high dielectric materials for light-sensitive capacitance applications. By using ultraviolet photoemission spectroscopy (UPS), we show here that exposure of BLFO surfaces to UV light induces a counterintuitive shift of the O2p valence state to lower binding energy of up to 243 meV which is a direct signature of negative electronic compressibility (NEC). A decrease of BLFO electrical resistance agrees strongly with the UPS data suggesting the creation of a thin conductive layer on its insulating bulk under light irradiation. By exploiting the quantum capacitance model, we find that the negative quantum capacitance due to this NEC effect plays an important role in this capacitance enhancement
Collapse
Affiliation(s)
- S Nathabumroong
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - T Eknapakul
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - P Jaiban
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.,Faculty of science, Energy and Environment, King Mongkut's University of Technology North Bangkok, Rayong Campus, Rayong, 21120, Thailand
| | - B Yotburut
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.,Thailand Center of Excellence in Physics (ThEP), MHSRI, Bangkok, 10400, Thailand
| | - S Siriroj
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - T Saisopa
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - S-K Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - R Supruangnet
- Synchrotron Light Research Institute, Nakhon Ratchasima, 30000, Thailand
| | - H Nakajima
- Synchrotron Light Research Institute, Nakhon Ratchasima, 30000, Thailand
| | - R Yimnirun
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.,School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong, 21210, Thailand
| | - S Maensiri
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - W Meevasana
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand. .,Thailand Center of Excellence in Physics (ThEP), MHSRI, Bangkok, 10400, Thailand.
| |
Collapse
|
3
|
Clark OJ, Neat MJ, Okawa K, Bawden L, Marković I, Mazzola F, Feng J, Sunko V, Riley JM, Meevasana W, Fujii J, Vobornik I, Kim TK, Hoesch M, Sasagawa T, Wahl P, Bahramy MS, King PDC. Fermiology and Superconductivity of Topological Surface States in PdTe_{2}. Phys Rev Lett 2018; 120:156401. [PMID: 29756894 DOI: 10.1103/physrevlett.120.156401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/17/2018] [Indexed: 05/12/2023]
Abstract
We study the low-energy surface electronic structure of the transition-metal dichalcogenide superconductor PdTe_{2} by spin- and angle-resolved photoemission, scanning tunneling microscopy, and density-functional theory-based supercell calculations. Comparing PdTe_{2} with its sister compound PtSe_{2}, we demonstrate how enhanced interlayer hopping in the Te-based material drives a band inversion within the antibonding p-orbital manifold well above the Fermi level. We show how this mediates spin-polarized topological surface states which form rich multivalley Fermi surfaces with complex spin textures. Scanning tunneling spectroscopy reveals type-II superconductivity at the surface, and moreover shows no evidence for an unconventional component of its superconducting order parameter, despite the presence of topological surface states.
Collapse
Affiliation(s)
- O J Clark
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - M J Neat
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - K Okawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - L Bawden
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - I Marković
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - F Mazzola
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - J Feng
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
- Suzhou Institute of Nano-Tech. and Nanobionics (SINANO), CAS, 398 Ruoshui Road, SEID, SIP, Suzhou 215123, China
| | - V Sunko
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - J M Riley
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - W Meevasana
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
- ThEP, Commission of Higher Education, Bangkok 10400, Thailand
| | - J Fujii
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - I Vobornik
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - T Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - P Wahl
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - M S Bahramy
- Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - P D C King
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| |
Collapse
|
4
|
Bahramy MS, Clark OJ, Yang BJ, Feng J, Bawden L, Riley JM, Marković I, Mazzola F, Sunko V, Biswas D, Cooil SP, Jorge M, Wells JW, Leandersson M, Balasubramanian T, Fujii J, Vobornik I, Rault JE, Kim TK, Hoesch M, Okawa K, Asakawa M, Sasagawa T, Eknapakul T, Meevasana W, King PDC. Ubiquitous formation of bulk Dirac cones and topological surface states from a single orbital manifold in transition-metal dichalcogenides. Nat Mater 2018; 17:21-28. [PMID: 29180775 DOI: 10.1038/nmat5031] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 10/13/2017] [Indexed: 05/12/2023]
Abstract
Transition-metal dichalcogenides (TMDs) are renowned for their rich and varied bulk properties, while their single-layer variants have become one of the most prominent examples of two-dimensional materials beyond graphene. Their disparate ground states largely depend on transition metal d-electron-derived electronic states, on which the vast majority of attention has been concentrated to date. Here, we focus on the chalcogen-derived states. From density-functional theory calculations together with spin- and angle-resolved photoemission, we find that these generically host a co-existence of type-I and type-II three-dimensional bulk Dirac fermions as well as ladders of topological surface states and surface resonances. We demonstrate how these naturally arise within a single p-orbital manifold as a general consequence of a trigonal crystal field, and as such can be expected across a large number of compounds. Already, we demonstrate their existence in six separate TMDs, opening routes to tune, and ultimately exploit, their topological physics.
Collapse
Affiliation(s)
- M S Bahramy
- Quantum-Phase Electronics Center and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
- RIKEN center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - O J Clark
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - B-J Yang
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Korea
- Center for Theoretical Physics (CTP), Seoul National University, Seoul 08826, Korea
| | - J Feng
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO) CAS, 398 Ruoshi Road, SEID, SIP, Suzhou 215123, China
| | - L Bawden
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - J M Riley
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - I Marković
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - F Mazzola
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - V Sunko
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - D Biswas
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - S P Cooil
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - M Jorge
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - J W Wells
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - M Leandersson
- MAX IV Laboratory, Lund University, PO Box 118, 221 00 Lund, Sweden
| | | | - J Fujii
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - I Vobornik
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - J E Rault
- Synchrotron SOLEIL, CNRS-CEA, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - K Okawa
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - M Asakawa
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - T Sasagawa
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - T Eknapakul
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - W Meevasana
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
- ThEP, Commission of Higher Education, Bangkok 10400, Thailand
| | - P D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| |
Collapse
|
5
|
Wang Z, McKeown Walker S, Tamai A, Wang Y, Ristic Z, Bruno FY, de la Torre A, Riccò S, Plumb NC, Shi M, Hlawenka P, Sánchez-Barriga J, Varykhalov A, Kim TK, Hoesch M, King PDC, Meevasana W, Diebold U, Mesot J, Moritz B, Devereaux TP, Radovic M, Baumberger F. Tailoring the nature and strength of electron-phonon interactions in the SrTiO3(001) 2D electron liquid. Nat Mater 2016; 15:835-839. [PMID: 27064529 DOI: 10.1038/nmat4623] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 03/10/2016] [Indexed: 06/05/2023]
Abstract
Surfaces and interfaces offer new possibilities for tailoring the many-body interactions that dominate the electrical and thermal properties of transition metal oxides. Here, we use the prototypical two-dimensional electron liquid (2DEL) at the SrTiO3(001) surface to reveal a remarkably complex evolution of electron-phonon coupling with the tunable carrier density of this system. At low density, where superconductivity is found in the analogous 2DEL at the LaAlO3/SrTiO3 interface, our angle-resolved photoemission data show replica bands separated by 100 meV from the main bands. This is a hallmark of a coherent polaronic liquid and implies long-range coupling to a single longitudinal optical phonon branch. In the overdoped regime the preferential coupling to this branch decreases and the 2DEL undergoes a crossover to a more conventional metallic state with weaker short-range electron-phonon interaction. These results place constraints on the theoretical description of superconductivity and allow a unified understanding of the transport properties in SrTiO3-based 2DELs.
Collapse
Affiliation(s)
- Z Wang
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - S McKeown Walker
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - A Tamai
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Y Wang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Z Ristic
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - F Y Bruno
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - A de la Torre
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - S Riccò
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P Hlawenka
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, 12489 Berlin, Germany
| | - J Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, 12489 Berlin, Germany
| | - A Varykhalov
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, 12489 Berlin, Germany
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - P D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - W Meevasana
- School of Physics and NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - U Diebold
- Institute of Applied Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, A-1040 Vienna, Austria
| | - J Mesot
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - B Moritz
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T P Devereaux
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - M Radovic
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- SwissFEL, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - F Baumberger
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| |
Collapse
|
6
|
Riley JM, Meevasana W, Bawden L, Asakawa M, Takayama T, Eknapakul T, Kim TK, Hoesch M, Mo SK, Takagi H, Sasagawa T, Bahramy MS, King PDC. Negative electronic compressibility and tunable spin splitting in WSe2. Nat Nanotechnol 2015; 10:1043-1047. [PMID: 26389661 DOI: 10.1038/nnano.2015.217] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/20/2015] [Indexed: 06/05/2023]
Abstract
Tunable bandgaps, extraordinarily large exciton-binding energies, strong light-matter coupling and a locking of the electron spin with layer and valley pseudospins have established transition-metal dichalcogenides (TMDs) as a unique class of two-dimensional (2D) semiconductors with wide-ranging practical applications. Using angle-resolved photoemission (ARPES), we show here that doping electrons at the surface of the prototypical strong spin-orbit TMD WSe2, akin to applying a gate voltage in a transistor-type device, induces a counterintuitive lowering of the surface chemical potential concomitant with the formation of a multivalley 2D electron gas (2DEG). These measurements provide a direct spectroscopic signature of negative electronic compressibility (NEC), a result of electron-electron interactions, which we find persists to carrier densities approximately three orders of magnitude higher than in typical semiconductor 2DEGs that exhibit this effect. An accompanying tunable spin splitting of the valence bands further reveals a complex interplay between single-particle band-structure evolution and many-body interactions in electrostatically doped TMDs. Understanding and exploiting this will open up new opportunities for advanced electronic and quantum-logic devices.
Collapse
Affiliation(s)
- J M Riley
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - W Meevasana
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
- NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - L Bawden
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - M Asakawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - T Takayama
- Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan
- Max Planck Institute for Solid State Research, Stuttgart 70569, Germany
| | - T Eknapakul
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - S-K Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley California 94720, USA
| | - H Takagi
- Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan
- Max Planck Institute for Solid State Research, Stuttgart 70569, Germany
| | - T Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - M S Bahramy
- Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - P D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| |
Collapse
|
7
|
Eknapakul T, King PDC, Asakawa M, Buaphet P, He RH, Mo SK, Takagi H, Shen KM, Baumberger F, Sasagawa T, Jungthawan S, Meevasana W. Electronic structure of a quasi-freestanding MoS₂ monolayer. Nano Lett 2014; 14:1312-6. [PMID: 24552197 DOI: 10.1021/nl4042824] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Several transition-metal dichalcogenides exhibit a striking crossover from indirect to direct band gap semiconductors as they are thinned down to a single monolayer. Here, we demonstrate how an electronic structure characteristic of the isolated monolayer can be created at the surface of a bulk MoS2 crystal. This is achieved by intercalating potassium in the interlayer van der Waals gap, expanding its size while simultaneously doping electrons into the conduction band. Our angle-resolved photoemission measurements reveal resulting electron pockets centered at the K̅ and K' points of the Brillouin zone, providing the first momentum-resolved measurements of how the conduction band dispersions evolve to yield an approximately direct band gap of ∼1.8 eV in quasi-freestanding monolayer MoS2. As well as validating previous theoretical proposals, this establishes a novel methodology for manipulating electronic structure in transition-metal dichalcogenides, opening a new route for the generation of large-area quasi-freestanding monolayers for future fundamental study and use in practical applications.
Collapse
Affiliation(s)
- T Eknapakul
- School of Physics, Suranaree University of Technology , Nakhon Ratchasima, 30000, Thailand
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
King PDC, McKeown Walker S, Tamai A, de la Torre A, Eknapakul T, Buaphet P, Mo SK, Meevasana W, Bahramy MS, Baumberger F. Quasiparticle dynamics and spin–orbital texture of the SrTiO3 two-dimensional electron gas. Nat Commun 2014; 5:3414. [DOI: 10.1038/ncomms4414] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 02/07/2014] [Indexed: 11/10/2022] Open
|
9
|
Vishik IM, Hashimoto M, He RH, Lee WS, Schmitt F, Lu D, Moore RG, Zhang C, Meevasana W, Sasagawa T, Uchida S, Fujita K, Ishida S, Ishikado M, Yoshida Y, Eisaki H, Hussain Z, Devereaux TP, Shen ZX. Phase competition in trisected superconducting dome. Proc Natl Acad Sci U S A 2012; 109:18332-7. [PMID: 23093670 PMCID: PMC3494935 DOI: 10.1073/pnas.1209471109] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A detailed phenomenology of low energy excitations is a crucial starting point for microscopic understanding of complex materials, such as the cuprate high-temperature superconductors. Because of its unique momentum-space discrimination, angle-resolved photoemission spectroscopy (ARPES) is ideally suited for this task in the cuprates, where emergent phases, particularly superconductivity and the pseudogap, have anisotropic gap structure in momentum space. We present a comprehensive doping- and temperature-dependence ARPES study of spectral gaps in Bi(2)Sr(2)CaCu(2)O(8+δ), covering much of the superconducting portion of the phase diagram. In the ground state, abrupt changes in near-nodal gap phenomenology give spectroscopic evidence for two potential quantum critical points, p = 0.19 for the pseudogap phase and p = 0.076 for another competing phase. Temperature dependence reveals that the pseudogap is not static below T(c) and exists p > 0.19 at higher temperatures. Our data imply a revised phase diagram that reconciles conflicting reports about the endpoint of the pseudogap in the literature, incorporates phase competition between the superconducting gap and pseudogap, and highlights distinct physics at the edge of the superconducting dome.
Collapse
Affiliation(s)
- I. M. Vishik
- Stanford Institute for Materials and Energy Sciences and
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305
| | - M. Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025
| | - Rui-Hua He
- Department of Physics, Boston College, Chestnut Hill, MA 02467
| | - Wei-Sheng Lee
- Stanford Institute for Materials and Energy Sciences and
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305
| | - Felix Schmitt
- Stanford Institute for Materials and Energy Sciences and
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305
| | - Donghui Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025
| | - R. G. Moore
- Stanford Institute for Materials and Energy Sciences and
| | - C. Zhang
- State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China
| | - W. Meevasana
- School of Physics, Suranaree University of Technology, Muang, Nakhon Ratchasima 30000, Thailand
| | - T. Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan
| | - S. Uchida
- Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kazuhiro Fujita
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853
| | - S. Ishida
- Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - M. Ishikado
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Yoshiyuki Yoshida
- Superconducting Electronics Group, Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan; and
| | - Hiroshi Eisaki
- Superconducting Electronics Group, Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan; and
| | - Zahid Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Thomas P. Devereaux
- Stanford Institute for Materials and Energy Sciences and
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305
| | - Zhi-Xun Shen
- Stanford Institute for Materials and Energy Sciences and
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305
| |
Collapse
|
10
|
King PDC, He RH, Eknapakul T, Buaphet P, Mo SK, Kaneko Y, Harashima S, Hikita Y, Bahramy MS, Bell C, Hussain Z, Tokura Y, Shen ZX, Hwang HY, Baumberger F, Meevasana W. Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO3. Phys Rev Lett 2012; 108:117602. [PMID: 22540511 DOI: 10.1103/physrevlett.108.117602] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Indexed: 05/31/2023]
Abstract
We demonstrate the formation of a two-dimensional electron gas (2DEG) at the (100) surface of the 5d transition-metal oxide KTaO3. From angle-resolved photoemission, we find that quantum confinement lifts the orbital degeneracy of the bulk band structure and leads to a 2DEG composed of ladders of subband states of both light and heavy carriers. Despite the strong spin-orbit coupling, our measurements provide a direct upper bound for the potential Rashba spin splitting of only Δk(parallel)}~0.02 Å(-1) at the Fermi level. The polar nature of the KTaO3(100) surface appears to help mediate the formation of the 2DEG as compared to nonpolar SrTiO3(100).
Collapse
Affiliation(s)
- P D C King
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Hashimoto M, He RH, Testaud JP, Meevasana W, Moore RG, Lu DH, Yoshida Y, Eisaki H, Devereaux TP, Hussain Z, Shen ZX. Reaffirming the d(x2-y2) superconducting gap using the autocorrelation angle-resolved photoemission spectroscopy of Bi1.5Pb0.55Sr1.6La0.4CuO(6+δ). Phys Rev Lett 2011; 106:167003. [PMID: 21599403 DOI: 10.1103/physrevlett.106.167003] [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: 04/16/2010] [Indexed: 05/30/2023]
Abstract
Knowledge of the gap function is important to understand the pairing mechanism for high-temperature (T(c)) superconductivity. However, Fourier transform scanning tunneling spectroscopy (FT STS) and angle-resolved photoemission spectroscopy (ARPES) in the cuprates have reported contradictory gap functions, with FT-STS results deviating strongly from a canonical d(x2-y2) form. By applying an "octet model" analysis to autocorrelation ARPES, we reveal that a contradiction occurs because the octet model does not consider the effects of matrix elements and the pseudogap. This reaffirms the canonical d(x2-y2) superconducting gap around the node, which can be directly determined from ARPES. Further, our study suggests that the FT-STS reported fluctuating superconductivity around the node at far above T(c) is not necessary to explain the existence of the quasiparticle interference at low energy.
Collapse
Affiliation(s)
- M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
He RH, Hashimoto M, Karapetyan H, Koralek JD, Hinton JP, Testaud JP, Nathan V, Yoshida Y, Yao H, Tanaka K, Meevasana W, Moore RG, Lu DH, Mo SK, Ishikado M, Eisaki H, Hussain Z, Devereaux TP, Kivelson SA, Orenstein J, Kapitulnik A, Shen ZX. From a single-band metal to a high-temperature superconductor via two thermal phase transitions. Science 2011; 331:1579-83. [PMID: 21436447 DOI: 10.1126/science.1198415] [Citation(s) in RCA: 270] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The nature of the pseudogap phase of cuprate high-temperature superconductors is a major unsolved problem in condensed matter physics. We studied the commencement of the pseudogap state at temperature T* using three different techniques (angle-resolved photoemission spectroscopy, polar Kerr effect, and time-resolved reflectivity) on the same optimally doped Bi2201 crystals. We observed the coincident, abrupt onset at T* of a particle-hole asymmetric antinodal gap in the electronic spectrum, a Kerr rotation in the reflected light polarization, and a change in the ultrafast relaxational dynamics, consistent with a phase transition. Upon further cooling, spectroscopic signatures of superconductivity begin to grow close to the superconducting transition temperature (T(c)), entangled in an energy-momentum-dependent manner with the preexisting pseudogap features, ushering in a ground state with coexisting orders.
Collapse
Affiliation(s)
- Rui-Hua He
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
King PDC, Rosen JA, Meevasana W, Tamai A, Rozbicki E, Comin R, Levy G, Fournier D, Yoshida Y, Eisaki H, Shen KM, Ingle NJC, Damascelli A, Baumberger F. Structural origin of apparent Fermi surface pockets in angle-resolved photoemission of Bi₂Sr(2-x)La(x)CuO(6+δ). Phys Rev Lett 2011; 106:127005. [PMID: 21517346 DOI: 10.1103/physrevlett.106.127005] [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: 11/26/2010] [Indexed: 05/30/2023]
Abstract
We observe apparent hole pockets in the Fermi surfaces of single-layer Bi-based cuprate superconductors from angle-resolved photoemission. From detailed low-energy electron diffraction measurements and an analysis of the angle-resolved photoemission polarization dependence, we show that these pockets are not intrinsic but arise from multiple overlapping superstructure replicas of the main and shadow bands. We further demonstrate that the hole pockets reported recently from angle-resolved photoemission [Meng et al., Nature (London) 462, 335 (2009)] have a similar structural origin and are inconsistent with an intrinsic hole pocket associated with the electronic structure of a doped CuO₂ plane.
Collapse
Affiliation(s)
- P D C King
- School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Meevasana W, King PDC, He RH, Mo SK, Hashimoto M, Tamai A, Songsiriritthigul P, Baumberger F, Shen ZX. Creation and control of a two-dimensional electron liquid at the bare SrTiO3 surface. Nat Mater 2011; 10:114-8. [PMID: 21240289 DOI: 10.1038/nmat2943] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 12/10/2010] [Indexed: 05/24/2023]
Abstract
Many-body interactions in transition-metal oxides give rise to a wide range of functional properties, such as high-temperature superconductivity, colossal magnetoresistance or multiferroicity . The seminal recent discovery of a two-dimensional electron gas (2DEG) at the interface of the insulating oxides LaAlO(3) and SrTiO(3) (ref. 4) represents an important milestone towards exploiting such properties in all-oxide devices. This conducting interface shows a number of appealing properties, including a high electron mobility, superconductivity and large magnetoresistance, and can be patterned on the few-nanometre length scale. However, the microscopic origin of the interface 2DEG is poorly understood. Here, we show that a similar 2DEG, with an electron density as large as 8×10(13) cm(-2), can be formed at the bare SrTiO(3) surface. Furthermore, we find that the 2DEG density can be controlled through exposure of the surface to intense ultraviolet light. Subsequent angle-resolved photoemission spectroscopy measurements reveal an unusual coexistence of a light quasiparticle mass and signatures of strong many-body interactions.
Collapse
Affiliation(s)
- W Meevasana
- Department of Physics, Stanford University, California 94305, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Tamai A, Ganin AY, Rozbicki E, Bacsa J, Meevasana W, King PDC, Caffio M, Schaub R, Margadonna S, Prassides K, Rosseinsky MJ, Baumberger F. Strong electron correlations in the normal state of the iron-based FeSe0.42Te0.58 superconductor observed by angle-resolved photoemission spectroscopy. Phys Rev Lett 2010; 104:097002. [PMID: 20367005 DOI: 10.1103/physrevlett.104.097002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2009] [Indexed: 05/29/2023]
Abstract
We investigate the normal state of the "11" iron-based superconductor FeSe0.42Te0.58 by angle-resolved photoemission. Our data reveal a highly renormalized quasiparticle dispersion characteristic of a strongly correlated metal. We find sheet dependent effective carrier masses between approximately 3 and 16m{e} corresponding to a mass enhancement over band structure values of m{*}/m{band} approximately 6-20. This is nearly an order of magnitude higher than the renormalization reported previously for iron-arsenide superconductors of the "1111" and "122" families but fully consistent with the bulk specific heat.
Collapse
Affiliation(s)
- A Tamai
- School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife KY16 9SS, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Tamai A, Allan MP, Mercure JF, Meevasana W, Dunkel R, Lu DH, Perry RS, Mackenzie AP, Singh DJ, Shen ZX, Baumberger F. Fermi surface and van Hove singularities in the itinerant Metamagnet Sr3Ru2O7. Phys Rev Lett 2008; 101:026407. [PMID: 18764208 DOI: 10.1103/physrevlett.101.026407] [Citation(s) in RCA: 7] [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: 03/06/2008] [Indexed: 05/26/2023]
Abstract
The low-energy electronic structure of the itinerant metamagnet Sr3Ru2O7 is investigated by angle-resolved photoemission and density-functional calculations. We find well-defined quasiparticle bands with resolution-limited linewidths and Fermi velocities up to an order of magnitude lower than in single layer Sr2RuO4. The complete topography, the cyclotron masses, and the orbital character of the Fermi surface are determined, in agreement with bulk sensitive de Haas-van Alphen measurements. An analysis of the dxy band dispersion reveals a complex density of states with van Hove singularities near the Fermi level, a situation which is favorable for magnetic instabilities.
Collapse
Affiliation(s)
- A Tamai
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Shen KM, Kikugawa N, Bergemann C, Balicas L, Baumberger F, Meevasana W, Ingle NJC, Maeno Y, Shen ZX, Mackenzie AP. Evolution of the Fermi surface and quasiparticle renormalization through a van Hove singularity in Sr2-yLayRuO4. Phys Rev Lett 2007; 99:187001. [PMID: 17995427 DOI: 10.1103/physrevlett.99.187001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Indexed: 05/25/2023]
Abstract
We employ a combination of chemical substitution and angle resolved photoemission spectroscopy to prove that the Fermi level in the gamma band of Sr(2-y)La(y)RuO(4) can be made to traverse a van Hove singularity. Remarkably, the large mass renormalization has little dependence on either k or doping. By combining the results from photoemission with thermodynamic measurements on the same batches of crystals, we deduce a parametrization of the full many-body quasiparticle dispersion in Sr(2)RuO(4) which extends from the Fermi level to approximately 20 meV above it.
Collapse
Affiliation(s)
- K M Shen
- Department of Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Yang WL, Fabbri JD, Willey TM, Lee JRI, Dahl JE, Carlson RMK, Schreiner PR, Fokin AA, Tkachenko BA, Fokina NA, Meevasana W, Mannella N, Tanaka K, Zhou XJ, van Buuren T, Kelly MA, Hussain Z, Melosh NA, Shen ZX. Monochromatic Electron Photoemission from Diamondoid Monolayers. Science 2007; 316:1460-2. [PMID: 17556579 DOI: 10.1126/science.1141811] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We found monochromatic electron photoemission from large-area self-assembled monolayers of a functionalized diamondoid, [121]tetramantane-6-thiol. Photoelectron spectra of the diamondoid monolayers exhibited a peak at the low-kinetic energy threshold; up to 68% of all emitted electrons were emitted within this single energy peak. The intensity of the emission peak is indicative of diamondoids being negative electron affinity materials. With an energy distribution width of less than 0.5 electron volts, this source of monochromatic electrons may find application in technologies such as electron microscopy, electron beam lithography, and field-emission flat-panel displays.
Collapse
Affiliation(s)
- W L Yang
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Baumberger F, Ingle NJC, Meevasana W, Shen KM, Lu DH, Perry RS, Mackenzie AP, Hussain Z, Singh DJ, Shen ZX. Fermi surface and quasiparticle excitations of Sr2RhO4. Phys Rev Lett 2006; 96:246402. [PMID: 16907260 DOI: 10.1103/physrevlett.96.246402] [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: 12/30/2005] [Indexed: 05/11/2023]
Abstract
The electronic structure of the layered 4d transition metal oxide Sr2RhO4 is investigated by angle resolved photoemission. We find well-defined quasiparticle excitations with a highly anisotropic dispersion, suggesting a quasi-two-dimensional Fermi-liquid-like ground state. Markedly different from the isostructural Sr2RuO4, only two bands with dominant Rh 4dxz,zy character contribute to the Fermi surface. A quantitative analysis of the photoemission quasiparticle band structure is in excellent agreement with bulk data. In contrast, it is found that state-of-the-art density functional calculations in the local density approximation differ significantly from the experimental findings.
Collapse
Affiliation(s)
- F Baumberger
- Department of Applied Physics, and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Meevasana W, Ingle NJC, Lu DH, Shi JR, Baumberger F, Shen KM, Lee WS, Cuk T, Eisaki H, Devereaux TP, Nagaosa N, Zaanen J, Shen ZX. Doping dependence of the coupling of electrons to bosonic modes in the single-layer high-temperature Bi2Sr2CuO6 superconductor. Phys Rev Lett 2006; 96:157003. [PMID: 16712188 DOI: 10.1103/physrevlett.96.157003] [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: 09/01/2005] [Indexed: 05/09/2023]
Abstract
A recent highlight in the study of high-T(c) superconductors is the observation of band renormalization or self-energy effects on the quasiparticles. This is seen in the form of kinks in the quasiparticle dispersions as measured by photoemission and interpreted as signatures of collective bosonic modes coupling to the electrons. Here we compare for the first time the self-energies in an optimally doped and strongly overdoped, nonsuperconducting single-layer Bi-cuprate (Bi2Sr2CuO6). In addition to the appearance of a strong overall weakening, we also find that the weight of the self-energy in the overdoped system shifts to higher energies. We present evidence that this is related to a change in the coupling to c-axis phonons due to the rapid change of the c-axis screening in this doping range.
Collapse
Affiliation(s)
- W Meevasana
- Department of Physics, Applied Physics, and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Baumberger F, Ingle NJC, Kikugawa N, Hossain MA, Meevasana W, Perry RS, Shen KM, Lu DH, Damascelli A, Rost A, Mackenzie AP, Hussain Z, Shen ZX. Nested fermi surface and electronic instability in Ca3Ru2O7. Phys Rev Lett 2006; 96:107601. [PMID: 16605788 DOI: 10.1103/physrevlett.96.107601] [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: 07/15/2005] [Indexed: 05/08/2023]
Abstract
High-resolution angular resolved photoemission data reveal well-defined quasiparticle bands of unusually low weight, emerging in line with the metallic phase of Ca(3)Ru(2)O(7) below approximately 30 K . At the bulk structural phase transition temperature of 48 K, we find clear evidence for an electronic instability, gapping large parts of the underlying Fermi surface that appears to be nested. Metallic pockets are found to survive in the small, non-nested sections, constituting a low-temperature Fermi surface with 2 orders of magnitude smaller volume than in all other metallic ruthenates. The Fermi velocities and volumes of these pockets are in agreement with the results of complementary quantum oscillation measurements on the same crystal batches.
Collapse
Affiliation(s)
- F Baumberger
- Department of Applied Physics, and Stanford Synchrotron Radiation Laboratory, Stanford University, California 94305, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Shen KM, Ronning F, Lu DH, Baumberger F, Ingle NJC, Lee WS, Meevasana W, Kohsaka Y, Azuma M, Takano M, Takagi H, Shen ZX. Nodal quasiparticles and antinodal charge ordering in Ca2-xNaxCuO2Cl2. Science 2005; 307:901-4. [PMID: 15705845 DOI: 10.1126/science.1103627] [Citation(s) in RCA: 298] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Understanding the role of competing states in the cuprates is essential for developing a theory for high-temperature superconductivity. We report angle-resolved photoemission spectroscopy experiments which probe the 4a0 x 4a0 charge-ordered state discovered by scanning tunneling microscopy in the lightly doped cuprate superconductor Ca2-xNaxCuO2Cl2. Our measurements reveal a marked dichotomy between the real- and momentum-space probes, for which charge ordering is emphasized in the tunneling measurements and photoemission is most sensitive to excitations near the node of the d-wave superconducting gap. These results emphasize the importance of momentum anisotropy in determining the complex electronic properties of the cuprates and places strong constraints on theoretical models of the charge-ordered state.
Collapse
Affiliation(s)
- Kyle M Shen
- Departments of Applied Physics, Physics, and Stanford Synchrotron Laboratory, Stanford University, Stanford, CA 94305, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Shen KM, Ronning F, Lu DH, Lee WS, Ingle NJC, Meevasana W, Baumberger F, Damascelli A, Armitage NP, Miller LL, Kohsaka Y, Azuma M, Takano M, Takagi H, Shen ZX. Missing quasiparticles and the chemical potential puzzle in the doping evolution of the cuprate superconductors. Phys Rev Lett 2004; 93:267002. [PMID: 15698008 DOI: 10.1103/physrevlett.93.267002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Indexed: 05/24/2023]
Abstract
The evolution of Ca2-xNaxCuO2Cl2 from Mott insulator to superconductor was studied using angle-resolved photoemission spectroscopy. By measuring both the excitations near the Fermi energy as well as nonbonding states, we tracked the doping dependence of the electronic structure and the chemical potential with unprecedented precision. Our work reveals failures in the standard weakly interacting quasiparticle scenario, including the broad line shapes of the insulator and the apparently paradoxical shift of the chemical potential within the Mott gap. To resolve this, we develop a model where the quasiparticle is vanishingly small at half filling and grows upon doping, allowing us to unify properties such as the dispersion and Fermi wave vector with the chemical potential.
Collapse
Affiliation(s)
- K M Shen
- Department of Applied Physics, Physics, and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|