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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). PHYSICAL REVIEW LETTERS 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] [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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Nicolaou A, Brouet V, Zacchigna M, Vobornik I, Tejeda A, Taleb-Ibrahimi A, Le Fèvre P, Bertran F, Hébert S, Muguerra H, Grebille D. Experimental study of the incoherent spectral weight in the photoemission spectra of the misfit cobaltate [Bi_{2}Ba{2}O{4}][CoO{2}]{2}. PHYSICAL REVIEW LETTERS 2010; 104:056403. [PMID: 20366778 DOI: 10.1103/physrevlett.104.056403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Indexed: 05/29/2023]
Abstract
Previous angle-resolved photoemission spectroscopy experiments in NaxCoO2 reported both a strongly renormalized bandwidth near the Fermi level and moderately renormalized Fermi velocities, leaving it unclear whether the correlations are weak or strong and how they could be quantified. We explain why this situation occurs and solve the problem by extracting clearly the coherent and incoherent parts of the band crossing the Fermi level. We show that one can use their relative weight to estimate self-consistently a quasiparticle weight Z=0.15+/-0.05. We suggest this method could be a reliable way to study the evolution of correlations in cobaltates and for comparison with other strongly correlated systems.
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Affiliation(s)
- A Nicolaou
- Laboratoire de Physique des Solides, Université Paris-Sud, UMR8502, Bât 510, 91405 Orsay, France
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