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Yu TL, Xu M, Yang WT, Song YH, Wen CHP, Yao Q, Lou X, Zhang T, Li W, Wei XY, Bao JK, Cao GH, Dudin P, Denlinger JD, Strocov VN, Peng R, Xu HC, Feng DL. Strong band renormalization and emergent ferromagnetism induced by electron-antiferromagnetic-magnon coupling. Nat Commun 2022; 13:6560. [PMID: 36323685 PMCID: PMC9630309 DOI: 10.1038/s41467-022-34254-0] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 10/13/2022] [Indexed: 11/15/2022] Open
Abstract
The interactions between electrons and antiferromagnetic magnons (AFMMs) are important for a large class of correlated materials. For example, they are the most plausible pairing glues in high-temperature superconductors, such as cuprates and iron-based superconductors. However, unlike electron-phonon interactions (EPIs), clear-cut observations regarding how electron-AFMM interactions (EAIs) affect the band structure are still lacking. Consequently, critical information on the EAIs, such as its strength and doping dependence, remains elusive. Here we directly observe that EAIs induce a kink structure in the band dispersion of Ba1-xKxMn2As2, and subsequently unveil several key characteristics of EAIs. We found that the coupling constant of EAIs can be as large as 5.4, and it shows strong doping dependence and temperature dependence, all in stark contrast to the behaviors of EPIs. The colossal renormalization of electron bands by EAIs enhances the density of states at Fermi energy, which is likely driving the emergent ferromagnetic state in Ba1-xKxMn2As2 through a Stoner-like mechanism with mixed itinerant-local character. Our results expand the current knowledge of EAIs, which may facilitate the further understanding of many correlated materials where EAIs play a critical role.
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Affiliation(s)
- T. L. Yu
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - M. Xu
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - W. T. Yang
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - Y. H. Song
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - C. H. P. Wen
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - Q. Yao
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - X. Lou
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - T. Zhang
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China ,grid.9227.e0000000119573309Shanghai Research Center for Quantum Sciences, 201315 Shanghai, P. R. China ,grid.509497.6Collaborative Innovation Center of Advanced Microstructures, 210093 Nanjing, China
| | - W. Li
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - X. Y. Wei
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - J. K. Bao
- grid.13402.340000 0004 1759 700XDepartment of Physics, Zhejiang University, 310027 Hangzhou, P. R. China
| | - G. H. Cao
- grid.13402.340000 0004 1759 700XDepartment of Physics, Zhejiang University, 310027 Hangzhou, P. R. China
| | - P. Dudin
- grid.18785.330000 0004 1764 0696Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE UK
| | - J. D. Denlinger
- grid.184769.50000 0001 2231 4551Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720-8229 USA
| | - V. N. Strocov
- grid.5991.40000 0001 1090 7501Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, PSI Switzerland
| | - R. Peng
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China ,grid.9227.e0000000119573309Shanghai Research Center for Quantum Sciences, 201315 Shanghai, P. R. China
| | - H. C. Xu
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - D. L. Feng
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China ,grid.9227.e0000000119573309Shanghai Research Center for Quantum Sciences, 201315 Shanghai, P. R. China ,grid.509497.6Collaborative Innovation Center of Advanced Microstructures, 210093 Nanjing, China ,grid.59053.3a0000000121679639Hefei National Laboratory for Physical Science at Microscale, CAS Center for Excellence in Quantum Information and Quantum Physics, and Department of Physics, University of Science and Technology of China, 230026 Hefei, P. R. China
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2
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Lou X, Yu TL, Song YH, Wen CHP, Wei WZ, Leithe-Jasper A, Ding ZF, Shu L, Kirchner S, Xu HC, Peng R, Feng DL. Distinct Kondo Screening Behaviors in Heavy Fermion Filled Skutterudites with 4f^{1} and 4f^{2} Configurations. Phys Rev Lett 2021; 126:136402. [PMID: 33861107 DOI: 10.1103/physrevlett.126.136402] [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: 06/08/2020] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
CeOs_{4}Sb_{12} (COS) and PrOs_{4}Sb_{12} (POS) are two representative compounds that provide the ideal vantage point to systematically study the physics of multi-f-electron systems. COS with Ce 4f^{1}, and POS with Pr 4f^{2} configurations show distinct properties of Kondo insulating and heavy fermion superconductivity, respectively. We unveiled the underlying microscopic origin by angle-resolved photoemission spectroscopy studies. Their eV-scale band structure matches well, representing the common characters of conduction electrons in ROs_{4}Sb_{12} systems (R=rare earth). However, f electrons interact differently with conduction electrons in COS and POS. Strong hybridization between conduction electrons and f electrons is observed in COS with band dependent hybridization gaps, and the development of a Kondo insulating state is directly revealed. Although the ground state of POS is a singlet, finite but incoherent hybridization exists, which can be explained by the Kondo scattering with the thermally excited triplet crystalline electric field state. Our results help us to understand the intriguing properties in COS and POS, and provide a clean demonstration of the microscopic differences in heavy fermion systems with 4f^{1} and 4f^{2} configurations.
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Affiliation(s)
- X Lou
- Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - T L Yu
- Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - Y H Song
- Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - C H P Wen
- Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - W Z Wei
- Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - A Leithe-Jasper
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straβe 40, 01187 Dresden, Germany
| | - Z F Ding
- Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - L Shu
- Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - S Kirchner
- Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027, China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou 310027, China
| | - H C Xu
- Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - R Peng
- Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - D L Feng
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
- Hefei National Laboratory for Physical Science at Microscale, CAS Center for Excellence in Quantum Information and Quantum Physics, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
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3
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Wen CHP, Xu HC, Yao Q, Peng R, Niu XH, Chen QY, Liu ZT, Shen DW, Song Q, Lou X, Fang YF, Liu XS, Song YH, Jiao YJ, Duan TF, Wen HH, Dudin P, Kotliar G, Yin ZP, Feng DL. Unveiling the Superconducting Mechanism of Ba_{0.51}K_{0.49}BiO_{3}. Phys Rev Lett 2018; 121:117002. [PMID: 30265111 DOI: 10.1103/physrevlett.121.117002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 07/08/2018] [Indexed: 05/12/2023]
Abstract
The mechanism of high superconducting transition temperatures (T_{c}) in bismuthates remains under debate despite more than 30 years of extensive research. Our angle-resolved photoemission spectroscopy studies on Ba_{0.51}K_{0.49}BiO_{3} reveal an unexpectedly 34% larger bandwidth than in conventional density functional theory calculations. This can be reproduced by calculations that fully account for long-range Coulomb interactions-the first direct demonstration of bandwidth expansion due to the Fock exchange term, a long-accepted and yet uncorroborated fundamental effect in many body physics.Furthermore, we observe an isotropic superconducting gap with 2Δ_{0}/k_{B}T_{c}=3.51±0.05, and strong electron-phonon interactions with a coupling constant λ∼1.3±0.2. These findings solve a long-standing mystery-Ba_{0.51}K_{0.49}BiO_{3} is an extraordinary Bardeen-Cooper-Schrieffer superconductor, where long-range Coulomb interactions expand the bandwidth, enhance electron-phonon coupling, and generate the high T_{c}. Such effects will also be critical for finding new superconductors.
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Affiliation(s)
- C H P Wen
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - H C Xu
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - Q Yao
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - R Peng
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - X H Niu
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - Q Y Chen
- Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621908, China
| | - Z T Liu
- CAS Center for Excellence in Superconducting Electronics (CENSE), Shanghai 200050, China
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
| | - D W Shen
- CAS Center for Excellence in Superconducting Electronics (CENSE), Shanghai 200050, China
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
| | - Q Song
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - X Lou
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - Y F Fang
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - X S Liu
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - Y H Song
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
| | - Y J Jiao
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - T F Duan
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - H H Wen
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - P Dudin
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - G Kotliar
- Department of Physics, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Z P Yin
- Department of Physics and Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
| | - D L Feng
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
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4
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Yao Q, Shen DW, Wen CHP, Hua CQ, Zhang LQ, Wang NZ, Niu XH, Chen QY, Dudin P, Lu YH, Zheng Y, Chen XH, Wan XG, Feng DL. Charge Transfer Effects in Naturally Occurring van der Waals Heterostructures (PbSe)_{1.16}(TiSe_{2})_{m} (m=1, 2). Phys Rev Lett 2018; 120:106401. [PMID: 29570327 DOI: 10.1103/physrevlett.120.106401] [Citation(s) in RCA: 2] [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: 11/05/2017] [Indexed: 06/08/2023]
Abstract
van der Waals heterostructures (VDWHs) exhibit rich properties and thus has potential for applications, and charge transfer between different layers in a heterostructure often dominates its properties and device performance. It is thus critical to reveal and understand the charge transfer effects in VDWHs, for which electronic structure measurements have proven to be effective. Using angle-resolved photoemission spectroscopy, we studied the electronic structures of (PbSe)_{1.16}(TiSe_{2})_{m} (m=1, 2), which are naturally occurring VDWHs, and discovered several striking charge transfer effects. When the thickness of the TiSe_{2} layers is halved from m=2 to m=1, the amount of charge transferred increases unexpectedly by more than 250%. This is accompanied by a dramatic drop in the electron-phonon interaction strength far beyond the prediction by first-principles calculations and, consequently, superconductivity only exists in the m=2 compound with strong electron-phonon interaction, albeit with lower carrier density. Furthermore, we found that the amount of charge transferred in both compounds is nearly halved when warmed from below 10 K to room temperature, due to the different thermal expansion coefficients of the constituent layers of these misfit compounds. These unprecedentedly large charge transfer effects might widely exist in VDWHs composed of metal-semiconductor contacts; thus, our results provide important insights for further understanding and applications of VDWHs.
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Affiliation(s)
- Q Yao
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing 210093, China
| | - D W Shen
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- CAS Center for Excellence in Superconducting Electronics (CENSE), Shanghai 200050, China
| | - C H P Wen
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing 210093, China
| | - C Q Hua
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - L Q Zhang
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing 210093, China
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
| | - N Z Wang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics and Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei 230026, China
| | - X H Niu
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing 210093, China
| | - Q Y Chen
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing 210093, China
| | - P Dudin
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Y H Lu
- State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027, China
| | - Y Zheng
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - X H Chen
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing 210093, China
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics and Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei 230026, China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
| | - X G Wan
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing 210093, China
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
| | - D L Feng
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing 210093, China
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5
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Chen QY, Xu DF, Niu XH, Peng R, Xu HC, Wen CHP, Liu X, Shu L, Tan SY, Lai XC, Zhang YJ, Lee H, Strocov VN, Bisti F, Dudin P, Zhu JX, Yuan HQ, Kirchner S, Feng DL. Band Dependent Interlayer f-Electron Hybridization in CeRhIn_{5}. Phys Rev Lett 2018; 120:066403. [PMID: 29481263 DOI: 10.1103/physrevlett.120.066403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 01/02/2018] [Indexed: 06/08/2023]
Abstract
A key issue in heavy fermion research is how subtle changes in the hybridization between the 4f (5f) and conduction electrons can result in fundamentally different ground states. CeRhIn_{5} stands out as a particularly notable example: when replacing Rh with either Co or Ir, antiferromagnetism gives way to superconductivity. In this photoemission study of CeRhIn_{5}, we demonstrate that the use of resonant angle-resolved photoemission spectroscopy with polarized light allows us to extract detailed information on the 4f crystal field states and details on the 4f and conduction electron hybridization, which together determine the ground state. We directly observe weakly dispersive Kondo resonances of f electrons and identify two of the three Ce 4f_{5/2}^{1} crystal-electric-field levels and band-dependent hybridization, which signals that the hybridization occurs primarily between the Ce 4f states in the CeIn_{3} layer and two more three-dimensional bands composed of the Rh 4d and In 5p orbitals in the RhIn_{2} layer. Our results allow us to connect the properties observed at elevated temperatures with the unusual low-temperature properties of this enigmatic heavy fermion compound.
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Affiliation(s)
- Q Y Chen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621908, China
| | - D F Xu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - X H Niu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - R Peng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - H C Xu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - C H P Wen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - X Liu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - L Shu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - S Y Tan
- Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621908, China
| | - X C Lai
- Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621908, China
| | - Y J Zhang
- Center for Correlated Matter, Zhejiang University, Hangzhou 310058, China
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - H Lee
- Center for Correlated Matter, Zhejiang University, Hangzhou 310058, China
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - F Bisti
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - P Dudin
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - J-X Zhu
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H Q Yuan
- Center for Correlated Matter, Zhejiang University, Hangzhou 310058, China
- Department of Physics, Zhejiang University, Hangzhou 310027, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - S Kirchner
- Center for Correlated Matter, Zhejiang University, Hangzhou 310058, China
| | - D L Feng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
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6
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Zhang WH, Liu X, Wen CHP, Peng R, Tan SY, Xie BP, Zhang T, Feng DL. Effects of Surface Electron Doping and Substrate on the Superconductivity of Epitaxial FeSe Films. Nano Lett 2016; 16:1969-1973. [PMID: 26859620 DOI: 10.1021/acs.nanolett.5b05243] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Superconductivity in FeSe is greatly enhanced in films grown on SrTiO3 substrates, although the mechanism behind remains unclear. Recently, surface potassium (K) doping has also proven able to enhance the superconductivity of FeSe. Here, by using scanning tunneling microscopy, we compare the K doping dependence of the superconductivity in FeSe films grown on two substrates: SrTiO3 (001) and graphitized SiC (0001). For thick films (20 unit cells (UC)), the optimized superconducting (SC) gaps are of similar size (∼9 meV) regardless of the substrate. However, when the thickness is reduced to a few UC, the optimized SC gap is increased up to ∼15 meV for films on SrTiO3, whereas it remains unchanged for films on SiC. This clearly indicates that the FeSe/SrTiO3 interface can further enhance the superconductivity, beyond merely doping electrons. Intriguingly, we found that this interface enhancement decays exponentially as the thickness increases, with a decay length of 2.4 UC, which is much shorter than the length scale for relaxation of the lattice strain, pointing to interfacial electron-phonon coupling as the likely origin.
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Affiliation(s)
- W H Zhang
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University , Shanghai 200433, China
| | - X Liu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University , Shanghai 200433, China
| | - C H P Wen
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University , Shanghai 200433, China
| | - R Peng
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University , Shanghai 200433, China
| | - S Y Tan
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University , Shanghai 200433, China
| | - B P Xie
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China
| | - T Zhang
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China
| | - D L Feng
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China
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7
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Wen CHP, Xu HC, Chen C, Huang ZC, Lou X, Pu YJ, Song Q, Xie BP, Abdel-Hafiez M, Chareev DA, Vasiliev AN, Peng R, Feng DL. Anomalous correlation effects and unique phase diagram of electron-doped FeSe revealed by photoemission spectroscopy. Nat Commun 2016; 7:10840. [PMID: 26952215 PMCID: PMC4786746 DOI: 10.1038/ncomms10840] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [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: 10/10/2015] [Accepted: 01/26/2016] [Indexed: 12/03/2022] Open
Abstract
FeSe layer-based superconductors exhibit exotic and distinctive properties. The undoped FeSe shows nematicity and superconductivity, while the heavily electron-doped KxFe2−ySe2 and single-layer FeSe/SrTiO3 possess high superconducting transition temperatures that pose theoretical challenges. However, a comprehensive study on the doping dependence of an FeSe layer-based superconductor is still lacking due to the lack of a clean means of doping control. Through angle-resolved photoemission spectroscopy studies on K-dosed thick FeSe films and FeSe0.93S0.07 bulk crystals, here we reveal the internal connections between these two types of FeSe-based superconductors, and obtain superconductivity below ∼46 K in an FeSe layer under electron doping without interfacial effects. Moreover, we discover an exotic phase diagram of FeSe with electron doping, including a nematic phase, a superconducting dome, a correlation-driven insulating phase and a metallic phase. Such an anomalous phase diagram unveils the remarkable complexity, and highlights the importance of correlations in FeSe layer-based superconductors. Electron doping is a powerful way to induce quantum phase transitions in materials and explore exotic states of matter. Here, Wen et al. present carefully-controlled potassium dosing in FeSe films and FeSe0.93S0.07 bulk, which enhances superconductivity and induces other anomalous phases, revealing a complex phase diagram.
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Affiliation(s)
- C H P Wen
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - H C Xu
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - C Chen
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - Z C Huang
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - X Lou
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - Y J Pu
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - Q Song
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - B P Xie
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - Mahmoud Abdel-Hafiez
- Institute of Physics, Goethe University Frankfurt, 60438 Frankfurt, Germany.,Center for High Pressure Science and Technology Advanced Research, 1690 Cailun Road, Shanghai 201203, China
| | - D A Chareev
- Institute of Experimental Mineralogy, Russian Academy of Sciences, Chernogolovka, 119991 Moscow , Russia
| | - A N Vasiliev
- Low Temperature Physics and Superconductivity Department, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - R Peng
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - D L Feng
- State Key Laboratory of Surface Physics, Department of Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
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Xia M, Jiang J, Niu XH, Liu JZ, Wen CHP, Lu HY, Lou X, Pu YJ, Huang ZC, Zhu X, Wen HH, Xie BP, Shen DW, Feng DL. Electronic structure of a new layered bismuth oxyselenide superconductor: LaO0.5F0.5BiSe2. J Phys Condens Matter 2015; 27:285502. [PMID: 26102451 DOI: 10.1088/0953-8984/27/28/285502] [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: 06/04/2023]
Abstract
LaO(0.5)F(0.5)BiSe(2) is a new layered superconductor discovered recently, which shows the superconducting transition temperature of 3.5 K. With angle-resolved photoemission spectroscopy, we study the electronic structure of LaO(0.5)F(0.5)BiSe(2) comprehensively. Two electron-like bands are located around the X point of the Brillouin zone, and the outer pockets connect with each other and form large Fermi surface around Γ and M. These bands show negligible k(z) dispersion, indicating their two-dimensional nature. Based on the Luttinger theorem, the carrier concentration is about 0.53 e(-) per unit cell, close to its nominal value. Moreover, the photoemission data and the band structure calculations agree very well, and the renormalization factor is nearly 1.0, indicating the electron correlations in this material are rather weak. Our results suggest that LaO(0.5)F(0.5)BiSe(2) is a conventional BCS superconductor without strong electron correlations.
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Affiliation(s)
- M Xia
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, People's Republic of China. Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, People's Republic of China
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