1
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Huber M, Lin Y, Marini G, Moreschini L, Jozwiak C, Bostwick A, Calandra M, Lanzara A. Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe 2. Sci Adv 2024; 10:eadl4481. [PMID: 38728393 PMCID: PMC11086600 DOI: 10.1126/sciadv.adl4481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 04/09/2024] [Indexed: 05/12/2024]
Abstract
Screening, a ubiquitous phenomenon associated with the shielding of electric fields by surrounding charges, has been widely adopted as a means to modify a material's properties. While most studies have relied on static changes of screening through doping or gating thus far, here we demonstrate that screening can also drive the onset of distinct quantum states on the ultrafast timescale. By using time- and angle-resolved photoemission spectroscopy, we show that intense optical excitation can drive 1T-TiSe2, a prototypical charge density wave material, almost instantly from a gapped into a semimetallic state. By systematically comparing changes in band structure over time and excitation strength with theoretical calculations, we find that the appearance of this state is likely caused by a dramatic reduction of the screening length. In summary, this work showcases how optical excitation enables the screening-driven design of a nonequilibrium semimetallic phase in TiSe2, possibly providing a general pathway into highly screened phases in other strongly correlated materials.
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Affiliation(s)
- Maximilian Huber
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yi Lin
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Giovanni Marini
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, I-16163 Genova, Italy
- Department of Physics, University of Trento, 38123 Povo, Italy
| | - Luca Moreschini
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Matteo Calandra
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, I-16163 Genova, Italy
- Department of Physics, University of Trento, 38123 Povo, Italy
- Sorbonne Universite, CNRS, Institut des Nanosciences de Paris, F-75252 Paris, France
| | - Alessandra Lanzara
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Physics Department, University of California, Berkeley, Berkeley, CA 94720, USA
- Kavli Energy NanoScience Institute, Berkeley, CA 94720, USA
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2
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Dale N, Utama MIB, Lee D, Leconte N, Zhao S, Lee K, Taniguchi T, Watanabe K, Jozwiak C, Bostwick A, Rotenberg E, Koch RJ, Jung J, Wang F, Lanzara A. Layer-Dependent Interaction Effects in the Electronic Structure of Twisted Bilayer Graphene Devices. Nano Lett 2023; 23:6799-6806. [PMID: 37486984 PMCID: PMC10424631 DOI: 10.1021/acs.nanolett.3c00253] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 05/25/2023] [Indexed: 07/26/2023]
Abstract
Near the magic angle, strong correlations drive many intriguing phases in twisted bilayer graphene (tBG) including unconventional superconductivity and chern insulation. Whether correlations can tune symmetry breaking phases in tBG at intermediate (≳ 2°) twist angles remains an open fundamental question. Here, using ARPES, we study the effects of many-body interactions and displacement field on the band structure of tBG devices at an intermediate (3°) twist angle. We observe a layer- and doping-dependent renormalization of bands at the K points that is qualitatively consistent with moiré models of the Hartree-Fock interaction. We provide evidence of correlation-enhanced inversion symmetry-breaking, manifested by gaps at the Dirac points that are tunable with doping. These results suggest that electronic interactions play a significant role in the physics of tBG even at intermediate twist angles and present a new pathway toward engineering band structure and symmetry-breaking phases in moiré heterostructures.
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Affiliation(s)
- Nicholas Dale
- Department
of Physics, University of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - M. Iqbal Bakti Utama
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Department
of Materials Science and Engineering, University
of California at Berkeley, Berkeley, California 94720, United States
| | - Dongkyu Lee
- Department
of Physics, University of Seoul, Seoul, 02504, Korea
- Department
of Smart Cities, University of Seoul, Seoul, 02504, Korea
| | - Nicolas Leconte
- Department
of Physics, University of Seoul, Seoul, 02504, Korea
| | - Sihan Zhao
- Interdisciplinary
Center for Quantum Information, Zhejiang Province Key Laboratory of
Quantum Technology and Device, State Key Laboratory of Silicon Materials,
and School of Physics, Zhejiang University, Hangzhou 310027, China
| | - Kyunghoon Lee
- Department
of Physics, University of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Chris Jozwiak
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Aaron Bostwick
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Eli Rotenberg
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Roland J. Koch
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Jeil Jung
- Department
of Physics, University of Seoul, Seoul, 02504, Korea
- Department
of Smart Cities, University of Seoul, Seoul, 02504, Korea
| | - Feng Wang
- Department
of Physics, University of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoScience
Institute at University of California Berkeley
and Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Alessandra Lanzara
- Department
of Physics, University of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoScience
Institute at University of California Berkeley
and Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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3
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Liu B, Kuang MQ, Luo Y, Li Y, Hu C, Liu J, Xiao Q, Zheng X, Huai L, Peng S, Wei Z, Shen J, Wang B, Miao Y, Sun X, Ou Z, Cui S, Sun Z, Hashimoto M, Lu D, Jozwiak C, Bostwick A, Rotenberg E, Moreschini L, Lanzara A, Wang Y, Peng Y, Yao Y, Wang Z, He J. Tunable Van Hove Singularity without Structural Instability in Kagome Metal CsTi_{3}Bi_{5}. Phys Rev Lett 2023; 131:026701. [PMID: 37505968 DOI: 10.1103/physrevlett.131.026701] [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: 12/12/2022] [Revised: 03/24/2023] [Accepted: 06/05/2023] [Indexed: 07/30/2023]
Abstract
In kagome metal CsV_{3}Sb_{5}, multiple intertwined orders are accompanied by both electronic and structural instabilities. These exotic orders have attracted much recent attention, but their origins remain elusive. The newly discovered CsTi_{3}Bi_{5} is a Ti-based kagome metal to parallel CsV_{3}Sb_{5}. Here, we report angle-resolved photoemission experiments and first-principles calculations on pristine and Cs-doped CsTi_{3}Bi_{5} samples. Our results reveal that the van Hove singularity (vHS) in CsTi_{3}Bi_{5} can be tuned in a large energy range without structural instability, different from that in CsV_{3}Sb_{5}. As such, CsTi_{3}Bi_{5} provides a complementary platform to disentangle and investigate the electronic instability with a tunable vHS in kagome metals.
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Affiliation(s)
- Bo Liu
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Min-Quan Kuang
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, and School of Physical Science and Technology, Southwest University, Chongqing 400715, China
| | - Yang Luo
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yongkai Li
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Cheng Hu
- Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jiarui Liu
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29631, USA
| | - Qian Xiao
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Xiquan Zheng
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Linwei Huai
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shuting Peng
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhiyuan Wei
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jianchang Shen
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bingqian Wang
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yu Miao
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiupeng Sun
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhipeng Ou
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shengtao Cui
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhe Sun
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Makoto Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Donghui Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Eli Rotenberg
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Luca Moreschini
- Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA
| | - Alessandra Lanzara
- Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA
| | - Yao Wang
- Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29631, USA
| | - Yingying Peng
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Zhiwei Wang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314011, China
| | - Junfeng He
- Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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4
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Corbae P, Ciocys S, Varjas D, Kennedy E, Zeltmann S, Molina-Ruiz M, Griffin SM, Jozwiak C, Chen Z, Wang LW, Minor AM, Scott M, Grushin AG, Lanzara A, Hellman F. Observation of spin-momentum locked surface states in amorphous Bi 2Se 3. Nat Mater 2023; 22:200-206. [PMID: 36646794 DOI: 10.1038/s41563-022-01458-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Crystalline symmetries have played a central role in the identification and understanding of quantum materials. Here we investigate whether an amorphous analogue of a well known three-dimensional strong topological insulator has topological properties in the solid state. We show that amorphous Bi2Se3 thin films host a number of two-dimensional surface conduction channels. Our angle-resolved photoemission spectroscopy data are consistent with a dispersive two-dimensional surface state that crosses the bulk gap. Spin-resolved photoemission spectroscopy shows this state has an anti-symmetric spin texture, confirming the existence of spin-momentum locked surface states. We discuss these experimental results in light of theoretical photoemission spectra obtained with an amorphous topological insulator tight-binding model, contrasting it with alternative explanations. The discovery of spin-momentum locked surface states in amorphous materials opens a new avenue to characterize amorphous matter, and triggers the search for an overlooked subset of quantum materials outside of current classification schemes.
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Affiliation(s)
- Paul Corbae
- Department of Materials Science, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Samuel Ciocys
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Dániel Varjas
- QuTech and Kavli Institute of NanoScience, Delft University of Technology, Delft, The Netherlands
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - Ellis Kennedy
- Department of Materials Science, University of California, Berkeley, CA, USA
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Steven Zeltmann
- Department of Materials Science, University of California, Berkeley, CA, USA
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Sinéad M Griffin
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Zhanghui Chen
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Lin-Wang Wang
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Andrew M Minor
- Department of Materials Science, University of California, Berkeley, CA, USA
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mary Scott
- Department of Materials Science, University of California, Berkeley, CA, USA
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Adolfo G Grushin
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Alessandra Lanzara
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Frances Hellman
- Department of Materials Science, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
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5
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Huber M, Lin Y, Dale N, Sailus R, Tongay S, Kaindl RA, Lanzara A. Revealing the order parameter dynamics of 1T-TiSe[Formula: see text] following optical excitation. Sci Rep 2022; 12:15860. [PMID: 36151110 PMCID: PMC9508156 DOI: 10.1038/s41598-022-19319-w] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 08/26/2022] [Indexed: 11/09/2022] Open
Abstract
The formation of a charge density wave state is characterized by an order parameter. The way it is established provides unique information on both the role that correlation plays in driving the charge density wave formation and the mechanism behind its formation. Here we use time and angle resolved photoelectron spectroscopy to optically perturb the charge-density phase in 1T-TiSe[Formula: see text] and follow the recovery of its order parameter as a function of energy, momentum and excitation density. Our results reveal that two distinct orders contribute to the gap formation, a CDW order and pseudogap-like order, manifested by an overall robustness to optical excitation. A detailed analysis of the magnitude of the the gap as a function of excitation density and delay time reveals the excitonic long-range nature of the CDW gap and the short-range Jahn-Teller character of the pseudogap order. In contrast to the gap, the intensity of the folded Se[Formula: see text]* band can only give access to the excitonic order. These results provide new information into the the long standing debate on the origin of the gap in TiSe[Formula: see text] and place it in the same context of other quantum materials where a pseudogap phase appears to be a precursor of long-range order.
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Affiliation(s)
- Maximilian Huber
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Yi Lin
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Nicholas Dale
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Physics Department, University of California Berkeley, Berkeley, CA 94720 USA
| | - Renee Sailus
- Materials Science and Engineering Department, Arizona State University, Phoenix, AZ 85281 USA
| | - Sefaattin Tongay
- Materials Science and Engineering Department, Arizona State University, Phoenix, AZ 85281 USA
| | - Robert A. Kaindl
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Department of Physics and CXFEL Labs, Arizona State University, Phoenix, AZ 85287 USA
| | - Alessandra Lanzara
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Physics Department, University of California Berkeley, Berkeley, CA 94720 USA
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6
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Mori R, Wang K, Morimoto T, Ciocys S, Denlinger JD, Paglione J, Lanzara A. Observation of a Flat and Extended Surface State in a Topological Semimetal. Materials (Basel) 2022; 15:ma15082744. [PMID: 35454435 PMCID: PMC9026440 DOI: 10.3390/ma15082744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 11/16/2022]
Abstract
A flat band structure in momentum space is considered key for the realization of novel phenomena. A topological flat band, also known as a drumhead state, is an ideal platform to drive new exotic topological quantum phases. Using angle-resolved photoemission spectroscopy experiments, we reveal the emergence of a highly localized surface state in a topological semimetal BaAl4 and provide its full energy and momentum space topology. We find that the observed surface state is localized in momentum, inside a square-shaped bulk Dirac nodal loop, and in energy, leading to a flat band and a peak in the density of state. These results imply this class of materials as an experimental realization of drumhead surface states and provide an important reference for future studies of the fundamental physics of correlated quantum effects in topological materials.
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Affiliation(s)
- Ryo Mori
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; (R.M.); (S.C.)
- Applied Science & Technology, University of California, Berkeley, CA 94720, USA
| | - Kefeng Wang
- Maryland Quantum Materials Center, Department of Physics, University of Maryland, College Park, MD 20742, USA; (K.W.); (J.P.)
| | - Takahiro Morimoto
- Department of Applied Physics, The University of Tokyo, Hongo, Tokyo 113-8656, Japan;
- JST, PRESTO, Kawaguchi 332-0012, Japan
| | - Samuel Ciocys
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; (R.M.); (S.C.)
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Jonathan D. Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA;
| | - Johnpierre Paglione
- Maryland Quantum Materials Center, Department of Physics, University of Maryland, College Park, MD 20742, USA; (K.W.); (J.P.)
| | - Alessandra Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; (R.M.); (S.C.)
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Correspondence:
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7
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Maksimovic N, Eilbott DH, Cookmeyer T, Wan F, Rusz J, Nagarajan V, Haley SC, Maniv E, Gong A, Faubel S, Hayes IM, Bangura A, Singleton J, Palmstrom JC, Winter L, McDonald R, Jang S, Ai P, Lin Y, Ciocys S, Gobbo J, Werman Y, Oppeneer PM, Altman E, Lanzara A, Analytis JG. Evidence for a delocalization quantum phase transition without symmetry breaking in CeCoIn 5. Science 2022; 375:76-81. [PMID: 34855511 DOI: 10.1126/science.aaz4566] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [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 study of quantum phase transitions that are not clearly associated with broken symmetry is a major effort in condensed matter physics, particularly in regard to the problem of high-temperature superconductivity, for which such transitions are thought to underlie the mechanism of superconductivity itself. Here we argue that the putative quantum critical point in the prototypical unconventional superconductor CeCoIn5 is characterized by the delocalization of electrons in a transition that connects two Fermi surfaces of different volumes, with no apparent broken symmetry. Drawing on established theory of f-electron metals, we discuss an interpretation for such a transition that involves the fractionalization of spin and charge, a model that effectively describes the anomalous transport behavior we measured for the Hall effect.
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Affiliation(s)
- Nikola Maksimovic
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Daniel H Eilbott
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Tessa Cookmeyer
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Fanghui Wan
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jan Rusz
- Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
| | - Vikram Nagarajan
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Shannon C Haley
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Eran Maniv
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Amanda Gong
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Stefano Faubel
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ian M Hayes
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ali Bangura
- National High Magnetic Field Laboratory, Tallahassee, FL 32310, USA
| | - John Singleton
- National High Magnetic Field Laboratory, Los Alamos, NM 97545, USA
| | | | - Laurel Winter
- National High Magnetic Field Laboratory, Los Alamos, NM 97545, USA
| | - Ross McDonald
- National High Magnetic Field Laboratory, Los Alamos, NM 97545, USA
| | - Sooyoung Jang
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ping Ai
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yi Lin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Samuel Ciocys
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jacob Gobbo
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yochai Werman
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Peter M Oppeneer
- Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
| | - Ehud Altman
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alessandra Lanzara
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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8
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Stansbury CH, Utama MIB, Fatuzzo CG, Regan EC, Wang D, Xiang Z, Ding M, Watanabe K, Taniguchi T, Blei M, Shen Y, Lorcy S, Bostwick A, Jozwiak C, Koch R, Tongay S, Avila J, Rotenberg E, Wang F, Lanzara A. Visualizing electron localization of WS 2/WSe 2 moiré superlattices in momentum space. Sci Adv 2021; 7:eabf4387. [PMID: 34516763 PMCID: PMC8442863 DOI: 10.1126/sciadv.abf4387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The search for materials with flat electronic bands continues due to their potential to drive strong correlation and symmetry breaking orders. Electronic moirés formed in van der Waals heterostructures have proved to be an ideal platform. However, there is no holistic experimental picture for how superlattices modify electronic structure. By combining spatially resolved angle-resolved photoemission spectroscopy with optical spectroscopy, we report the first direct evidence of how strongly correlated phases evolve from a weakly interacting regime in a transition metal dichalcogenide superlattice. By comparing short and long wave vector moirés, we find that the electronic structure evolves into a highly localized regime with increasingly flat bands and renormalized effective mass. The flattening is accompanied by the opening of a large gap in the spectral function and splitting of the exciton peaks. These results advance our understanding of emerging phases in moiré superlattices and point to the importance of interlayer physics.
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Affiliation(s)
- Conrad H. Stansbury
- Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Corresponding author. (C.H.S.); (A.L.)
| | - M. Iqbal Bakti Utama
- Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720, USA
| | - Claudia G. Fatuzzo
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Emma C. Regan
- Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Graduate Group in Applied Science and Technology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Danqing Wang
- Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Graduate Group in Applied Science and Technology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Ziyu Xiang
- Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
| | - Mingchao Ding
- Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Mark Blei
- School of Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287, USA
| | - Yuxia Shen
- School of Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287, USA
| | - Stéphane Lorcy
- Synchrotron-SOLEIL and Université Paris-Saclay Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France
| | - Aaron Bostwick
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Roland Koch
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Sefaattin Tongay
- School of Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287, USA
| | - José Avila
- Synchrotron-SOLEIL and Université Paris-Saclay Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France
| | - Eli Rotenberg
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Feng Wang
- Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alessandra Lanzara
- Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Corresponding author. (C.H.S.); (A.L.)
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9
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Mori R, Marshall PB, Ahadi K, Denlinger JD, Stemmer S, Lanzara A. Controlling a Van Hove singularity and Fermi surface topology at a complex oxide heterostructure interface. Nat Commun 2019; 10:5534. [PMID: 31797932 PMCID: PMC6892806 DOI: 10.1038/s41467-019-13046-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 09/06/2018] [Accepted: 10/16/2019] [Indexed: 11/10/2022] Open
Abstract
The emergence of saddle-point Van Hove singularities (VHSs) in the density of states, accompanied by a change in Fermi surface topology, Lifshitz transition, constitutes an ideal ground for the emergence of different electronic phenomena, such as superconductivity, pseudo-gap, magnetism, and density waves. However, in most materials the Fermi level, \documentclass[12pt]{minimal}
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\begin{document}$${E}_{{\rm{F}}}$$\end{document}EF, is too far from the VHS where the change of electronic topology takes place, making it difficult to reach with standard chemical doping or gating techniques. Here, we demonstrate that this scenario can be realized at the interface between a Mott insulator and a band insulator as a result of quantum confinement and correlation enhancement, and easily tuned by fine control of layer thickness and orbital occupancy. These results provide a tunable pathway for Fermi surface topology and VHS engineering of electronic phases. A singularity in a material’s density of states at the Fermi energy can drive the formation of unconventional electronic phases. Here the authors show a Van Hove singularity is tunable across the Fermi energy in an oxide heterostructure, leading to enhanced electronic correlations.
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Affiliation(s)
- Ryo Mori
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Applied Science & Technology, University of California, Berkeley, CA, 94720, USA
| | - Patrick B Marshall
- Materials Department, University of California, Santa Barbara, CA, 93106-5050, USA
| | - Kaveh Ahadi
- Materials Department, University of California, Santa Barbara, CA, 93106-5050, USA
| | - Jonathan D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Susanne Stemmer
- Materials Department, University of California, Santa Barbara, CA, 93106-5050, USA
| | - Alessandra Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,Department of Physics, University of California, Berkeley, CA, 94720, USA.
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10
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Latzke DW, Ojeda-Aristizabal C, Denlinger JD, Reno R, Zettl A, Lanzara A. Orbital Character Effects in the Photon Energy and Polarization Dependence of Pure C 60 Photoemission. ACS Nano 2019; 13:12710-12718. [PMID: 31638764 DOI: 10.1021/acsnano.9b04536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Recent direct experimental observation of multiple highly dispersive C60 valence bands has allowed for a detailed analysis of the unusual photoemission traits of these features through photon energy- and polarization-dependent measurements. Previously obscured dispersions and strong photoemission traits are now revealed by specific light polarizations. The observed intensity effects prove the locking in place of the C60 molecules at low temperatures and the existence of an orientational order imposed by the substrate chosen. Most importantly, photon energy- and polarization-dependent effects are shown to be intimately linked with the orbital character of the C60 band manifolds which allow for a more precise determination of the orbital character within the third highest occupied molecular orbital (HOMO-2). Our observations and analysis provide important considerations for the connection between molecular and crystalline C60 electronic structure, past and future band structure studies, and for increasingly popular C60 electronic device applications, especially those making use of heterostructures.
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Affiliation(s)
- Drew W Latzke
- Applied Science and Technology , University of California , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Claudia Ojeda-Aristizabal
- Department of Physics and Astronomy , California State University , Long Beach , California 90840 , United States
| | - Jonathan D Denlinger
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Ryan Reno
- Department of Physics and Astronomy , California State University , Long Beach , California 90840 , United States
| | - Alex Zettl
- Applied Science and Technology , University of California , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Alessandra Lanzara
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Department of Physics , University of California , Berkeley , California 94720 , United States
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11
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Buss JH, Wang H, Xu Y, Maklar J, Joucken F, Zeng L, Stoll S, Jozwiak C, Pepper J, Chuang YD, Denlinger JD, Hussain Z, Lanzara A, Kaindl RA. A setup for extreme-ultraviolet ultrafast angle-resolved photoelectron spectroscopy at 50-kHz repetition rate. Rev Sci Instrum 2019; 90:023105. [PMID: 30831755 DOI: 10.1063/1.5079677] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Time- and angle-resolved photoelectron spectroscopy (trARPES) is a powerful method to track the ultrafast dynamics of quasiparticles and electronic bands in energy and momentum space. We present a setup for trARPES with 22.3 eV extreme-ultraviolet (XUV) femtosecond pulses at 50-kHz repetition rate, which enables fast data acquisition and access to dynamics across momentum space with high sensitivity. The design and operation of the XUV beamline, pump-probe setup, and ultra-high vacuum endstation are described in detail. By characterizing the effect of space-charge broadening, we determine an ultimate source-limited energy resolution of 60 meV, with typically 80-100 meV obtained at 1-2 × 1010 photons/s probe flux on the sample. The instrument capabilities are demonstrated via both equilibrium and time-resolved ARPES studies of transition-metal dichalcogenides. The 50-kHz repetition rate enables sensitive measurements of quasiparticles at low excitation fluences in semiconducting MoSe2, with an instrumental time resolution of 65 fs. Moreover, photo-induced phase transitions can be driven with the available pump fluence, as shown by charge density wave melting in 1T-TiSe2. The high repetition-rate setup thus provides a versatile platform for sensitive XUV trARPES, from quenching of electronic phases down to the perturbative limit.
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Affiliation(s)
- Jan Heye Buss
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - He Wang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Yiming Xu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Julian Maklar
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Frederic Joucken
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Lingkun Zeng
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Sebastian Stoll
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - John Pepper
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Yi-De Chuang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jonathan D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Zahid Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Alessandra Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Robert A Kaindl
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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12
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Gotlieb K, Lin CY, Serbyn M, Zhang W, Smallwood CL, Jozwiak C, Eisaki H, Hussain Z, Vishwanath A, Lanzara A. Revealing hidden spin-momentum locking in a high-temperature cuprate superconductor. Science 2018; 362:1271-1275. [PMID: 30545882 DOI: 10.1126/science.aao0980] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 02/24/2018] [Accepted: 11/07/2018] [Indexed: 11/02/2022]
Abstract
Cuprate superconductors have long been thought of as having strong electronic correlations but negligible spin-orbit coupling. Using spin- and angle-resolved photoemission spectroscopy, we discovered that one of the most studied cuprate superconductors, Bi2212, has a nontrivial spin texture with a spin-momentum locking that circles the Brillouin zone center and a spin-layer locking that allows states of opposite spin to be localized in different parts of the unit cell. Our findings pose challenges for the vast majority of models of cuprates, such as the Hubbard model and its variants, where spin-orbit interaction has been mostly neglected, and open the intriguing question of how the high-temperature superconducting state emerges in the presence of this nontrivial spin texture.
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Affiliation(s)
- Kenneth Gotlieb
- Graduate Group in Applied Science and Technology, University of California, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Chiu-Yun Lin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Maksym Serbyn
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Wentao Zhang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Christopher L Smallwood
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Christopher Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Hiroshi Eisaki
- Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan
| | - Zahid Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Alessandra Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. .,Department of Physics, University of California, Berkeley, CA 94720, USA
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13
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Hwang J, Kim K, Ryu H, Kim J, Lee JE, Kim S, Kang M, Park BG, Lanzara A, Chung J, Mo SK, Denlinger J, Min BI, Hwang C. Emergence of Kondo Resonance in Graphene Intercalated with Cerium. Nano Lett 2018; 18:3661-3666. [PMID: 29761696 DOI: 10.1021/acs.nanolett.8b00784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The interaction between a magnetic impurity, such as cerium (Ce) atom, and surrounding electrons has been one of the core problems in understanding many-body interaction in solid and its relation to magnetism. Kondo effect, the formation of a new resonant ground state with quenched magnetic moment, provides a general framework to describe many-body interaction in the presence of magnetic impurity. In this Letter, a combined study of angle-resolved photoemission (ARPES) and dynamic mean-field theory (DMFT) on Ce-intercalated graphene shows that Ce-induced localized states near Fermi energy, EF, hybridized with the graphene π-band, exhibit gradual increase in spectral weight upon decreasing temperature. The observed temperature dependence follows the expectations from the Kondo picture in the weak coupling limit. Our results provide a novel insight how Kondo physics emerges in the sea of two-dimensional Dirac electrons.
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Affiliation(s)
- Jinwoong Hwang
- Department of Physics , Pusan National University , Busan 46241 , Korea
| | - Kyoo Kim
- Max Planck-POSTECH/Hsinchu Center for Complex Phase Materials , Pohang University of Science and Technology , Pohang 37673 , Korea
| | - Hyejin Ryu
- Department of Physics , Pusan National University , Busan 46241 , Korea
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Center for Spintronics , Korea Institute of Science and Technology , Seoul 02792 , Korea
| | - Jingul Kim
- Department of Physics , Pohang University of Science and Technology , Pohang 37673 , Korea
| | - Ji-Eun Lee
- Department of Physics , Pusan National University , Busan 46241 , Korea
| | - Sooran Kim
- Max Planck-POSTECH/Hsinchu Center for Complex Phase Materials , Pohang University of Science and Technology , Pohang 37673 , Korea
- Department of Physics , Pohang University of Science and Technology , Pohang 37673 , Korea
| | - Minhee Kang
- Department of Physics , Pusan National University , Busan 46241 , Korea
| | - Byeong-Gyu Park
- Pohang Accelerator Laboratory , Pohang University of Science and Technology , Pohang 37673 , Korea
| | - Alessandra Lanzara
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Jinwook Chung
- Department of Physics , Pohang University of Science and Technology , Pohang 37673 , Korea
- Department of Physics and Photon Science , Gwangju Institute of Science and Technology , Gwangju 61005 , Korea
| | - Sung-Kwan Mo
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Jonathan Denlinger
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Byung Il Min
- Department of Physics , Pohang University of Science and Technology , Pohang 37673 , Korea
| | - Choongyu Hwang
- Department of Physics , Pusan National University , Busan 46241 , Korea
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14
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Coslovich G, Kemper AF, Behl S, Huber B, Bechtel HA, Sasagawa T, Martin MC, Lanzara A, Kaindl RA. Ultrafast dynamics of vibrational symmetry breaking in a charge-ordered nickelate. Sci Adv 2017; 3:e1600735. [PMID: 29202025 PMCID: PMC5706742 DOI: 10.1126/sciadv.1600735] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
The ability to probe symmetry-breaking transitions on their natural time scales is one of the key challenges in nonequilibrium physics. Stripe ordering represents an intriguing type of broken symmetry, where complex interactions result in atomic-scale lines of charge and spin density. Although phonon anomalies and periodic distortions attest the importance of electron-phonon coupling in the formation of stripe phases, a direct time-domain view of vibrational symmetry breaking is lacking. We report experiments that track the transient multi-terahertz response of the model stripe compound La1.75Sr0.25NiO4, yielding novel insight into its electronic and structural dynamics following an ultrafast optical quench. We find that although electronic carriers are immediately delocalized, the crystal symmetry remains initially frozen-as witnessed by time-delayed suppression of zone-folded Ni-O bending modes acting as a fingerprint of lattice symmetry. Longitudinal and transverse vibrations react with different speeds, indicating a strong directionality and an important role of polar interactions. The hidden complexity of electronic and structural coupling during stripe melting and formation, captured here within a single terahertz spectrum, opens new paths to understanding symmetry-breaking dynamics in solids.
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Affiliation(s)
- Giacomo Coslovich
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Alexander F. Kemper
- Computational Research Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Sascha Behl
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Bernhard Huber
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Hans A. Bechtel
- Advanced Light Source, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Takao Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - Michael C. Martin
- Advanced Light Source, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alessandra Lanzara
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Robert A. Kaindl
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
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15
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Ryu H, Hwang J, Wang D, Disa AS, Denlinger J, Zhang Y, Mo SK, Hwang C, Lanzara A. Temperature-Dependent Electron-Electron Interaction in Graphene on SrTiO 3. Nano Lett 2017; 17:5914-5918. [PMID: 28906124 DOI: 10.1021/acs.nanolett.7b01650] [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] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The electron band structure of graphene on SrTiO3 substrate has been investigated as a function of temperature. The high-resolution angle-resolved photoemission study reveals that the spectral width at Fermi energy and the Fermi velocity of graphene on SrTiO3 are comparable to those of graphene on a BN substrate. Near the charge neutrality, the energy-momentum dispersion of graphene exhibits a strong deviation from the well-known linearity, which is magnified as temperature decreases. Such modification resembles the characteristics of enhanced electron-electron interaction. Our results not only suggest that SrTiO3 can be a plausible candidate as a substrate material for applications in graphene-based electronics but also provide a possible route toward the realization of a new type of strongly correlated electron phases in the prototypical two-dimensional system via the manipulation of temperature and a proper choice of dielectric substrates.
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Affiliation(s)
- Hyejin Ryu
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Max Planck-POSTECH/Hsinchu Center for Complex Phase Materials. Max Plank POSTECH/Korea Research Initiative (MPK) , Gyeongbuk 37673, South Korea
| | - Jinwoong Hwang
- Department of Physics, Pusan National University , Busan 46241, South Korea
| | - Debin Wang
- The Molecular Foundry, Lawrence Berkley National Laboratory , Berkeley, California 94720, United States
| | - Ankit S Disa
- Department of Applied Physics and Center for Interface Structures and Phenomena, Yale University , New Haven, Connecticut 06520, United States
| | - Jonathan Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Yuegang Zhang
- The Molecular Foundry, Lawrence Berkley National Laboratory , Berkeley, California 94720, United States
- Physics Department, Tsinghua University , Beijing 1000864, China
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Choongyu Hwang
- Department of Physics, Pusan National University , Busan 46241, South Korea
| | - Alessandra Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Department of Physics, University of California , Berkeley, California 94720, United States
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16
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Lo Vecchio I, Baldassarre L, Di Pietro P, Giorgianni F, Marsi M, Perucchi A, Schade U, Lanzara A, Lupi S. Orbital dependent coherence temperature and optical anisotropy of V 2O 3 quasiparticles. J Phys Condens Matter 2017; 29:345602. [PMID: 28665290 DOI: 10.1088/1361-648x/aa7cd7] [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] [Indexed: 06/07/2023]
Abstract
We report on an orbital and temperature dependent study of the onset of coherent quasiparticles in V2O3 single crystal. By using polarized infrared spectroscopy we demonstrate that the electronic coherence temperature is strongly orbital dependent, being about 400 K for [Formula: see text] orbitals and 500 K for the [Formula: see text]. This suggests that V2O3 low energy electrodynamics can be described in terms of two electron liquids differently renormalized by electronic correlations.
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Affiliation(s)
- I Lo Vecchio
- Dipartimento di Fisica, 'Sapienza' Università di Roma, Piazzale A. Moro 2, I-00185 Roma, Italy. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States of America
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17
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Hwang J, Hwang H, Kim MJ, Ryu H, Lee JE, Zhou Q, Mo SK, Lee J, Lanzara A, Hwang C. Hole doping, hybridization gaps, and electronic correlation in graphene on a platinum substrate. Nanoscale 2017; 9:11498-11503. [PMID: 28766659 DOI: 10.1039/c7nr03080k] [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: 06/07/2023]
Abstract
The interaction between graphene and substrates provides a viable route to enhance the functionality of both materials. Depending on the nature of electronic interaction at the interface, the electron band structure of graphene is strongly influenced, allowing us to make use of the intrinsic properties of graphene or to design additional functionalities in graphene. Here, we present an angle-resolved photoemission study on the interaction between graphene and a platinum substrate. The formation of an interface between graphene and platinum leads to a strong deviation in the electronic structure of graphene not only from its freestanding form but also from the behavior observed on typical metals. The combined study on the experimental and theoretical electron band structure unveils the unique electronic properties of graphene on a platinum substrate, which singles out graphene/platinum as a model system investigating graphene on a metallic substrate with strong interaction.
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Affiliation(s)
- Jinwoong Hwang
- Department of Physics, Pusan National University, Busan 46241, South Korea.
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18
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Ojeda-Aristizabal C, Santos EJG, Onishi S, Yan A, Rasool HI, Kahn S, Lv Y, Latzke DW, Velasco J, Crommie MF, Sorensen M, Gotlieb K, Lin CY, Watanabe K, Taniguchi T, Lanzara A, Zettl A. Molecular Arrangement and Charge Transfer in C 60/Graphene Heterostructures. ACS Nano 2017; 11:4686-4693. [PMID: 28437062 DOI: 10.1021/acsnano.7b00551] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Charge transfer at the interface between dissimilar materials is at the heart of electronics and photovoltaics. Here we study the molecular orientation, electronic structure, and local charge transfer at the interface region of C60 deposited on graphene, with and without supporting substrates such as hexagonal boron nitride. We employ ab initio density functional theory with van der Waals interactions and experimentally characterize interface devices using high-resolution transmission electron microscopy and electronic transport. Charge transfer between C60 and the graphene is found to be sensitive to the nature of the underlying supporting substrate and to the crystallinity and local orientation of the C60. Even at room temperature, C60 molecules interfaced to graphene are orientationally locked into position. High electron and hole mobilities are preserved in graphene with crystalline C60 overlayers, which has ramifications for organic high-mobility field-effect devices.
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Affiliation(s)
- Claudia Ojeda-Aristizabal
- Department of Physics, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California , Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Physics & Astronomy, California State University Long Beach , Long Beach, California 90840, United States
| | - Elton J G Santos
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
- School of Mathematics and Physics, Queen's University Belfast , Belfast BT7 1NN, United Kingdom
- School of Chemistry and Chemical Engineering, Queen's University Belfast , Belfast BT7 1NN, United Kingdom
| | - Seita Onishi
- Department of Physics, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California , Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Aiming Yan
- Department of Physics, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California , Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Haider I Rasool
- Department of Physics, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California , Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Salman Kahn
- Department of Physics, University of California , Berkeley, California 94720, United States
| | - Yinchuan Lv
- Department of Physics, University of California , Berkeley, California 94720, United States
| | - Drew W Latzke
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Graduate Group in Applied Science and Technology, University of California , Berkeley, California 94720, United States
| | - Jairo Velasco
- Department of Physics, University of California , Berkeley, California 94720, United States
| | - Michael F Crommie
- Department of Physics, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California , Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Matthew Sorensen
- Department of Physics, University of California , Berkeley, California 94720, United States
| | - Kenneth Gotlieb
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Graduate Group in Applied Science and Technology, University of California , Berkeley, California 94720, United States
| | - Chiu-Yun Lin
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Kenji Watanabe
- Advanced Materials Laboratory, National Institute for Materials Science , 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- Advanced Materials Laboratory, National Institute for Materials Science , 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan
| | - Alessandra Lanzara
- Department of Physics, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Alex Zettl
- Department of Physics, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California , Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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19
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Miller TL, Zhang W, Eisaki H, Lanzara A. Particle-Hole Asymmetry in the Cuprate Pseudogap Measured with Time-Resolved Spectroscopy. Phys Rev Lett 2017; 118:097001. [PMID: 28306293 DOI: 10.1103/physrevlett.118.097001] [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: 06/20/2016] [Indexed: 06/06/2023]
Abstract
One of the most puzzling features of high-temperature cuprate superconductors is the pseudogap state, which appears above the temperature at which superconductivity is destroyed. There remain fundamental questions regarding its nature and its relation to superconductivity. But to address these questions, we must first determine whether the pseudogap and superconducting states share a common property: particle-hole symmetry. We introduce a new technique to test particle-hole symmetry by using laser pulses to manipulate and measure the chemical potential on picosecond time scales. The results strongly suggest that the asymmetry in the density of states is inverted in the pseudogap state, implying a particle-hole asymmetric gap. Independent of interpretation, these results can test theoretical predictions of the density of states in cuprates.
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Affiliation(s)
- Tristan L Miller
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Wentao Zhang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hiroshi Eisaki
- Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan
| | - Alessandra Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
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20
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Lo Vecchio I, Denlinger JD, Krupin O, Kim BJ, Metcalf PA, Lupi S, Allen JW, Lanzara A. Fermi Surface of Metallic V_{2}O_{3} from Angle-Resolved Photoemission: Mid-level Filling of e_{g}^{π} Bands. Phys Rev Lett 2016; 117:166401. [PMID: 27792364 DOI: 10.1103/physrevlett.117.166401] [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: 05/27/2016] [Indexed: 06/06/2023]
Abstract
Using angle resolved photoemission spectroscopy, we report the first band dispersions and distinct features of the bulk Fermi surface (FS) in the paramagnetic metallic phase of the prototypical metal-insulator transition material V_{2}O_{3}. Along the c axis we observe both an electron pocket and a triangular holelike FS topology, showing that both V 3d a_{1g} and e_{g}^{π} states contribute to the FS. These results challenge the existing correlation-enhanced crystal field splitting theoretical explanation for the transition mechanism and pave the way for the solution of this mystery.
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Affiliation(s)
- I Lo Vecchio
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - J D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - O Krupin
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - B J Kim
- Max-Planck-Institut fur Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - P A Metcalf
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - S Lupi
- CNR-IOM and Dipartimento di Fisica, Università di Roma "Sapienza", I-00185 Rome, Italy
| | - J W Allen
- Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - A Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
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21
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Zhang W, Miller T, Smallwood CL, Yoshida Y, Eisaki H, Kaindl RA, Lee DH, Lanzara A. Stimulated emission of Cooper pairs in a high-temperature cuprate superconductor. Sci Rep 2016; 6:29100. [PMID: 27364682 PMCID: PMC4929572 DOI: 10.1038/srep29100] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/15/2016] [Indexed: 11/09/2022] Open
Abstract
The concept of stimulated emission of bosons has played an important role in modern science and technology, and constitutes the working principle for lasers. In a stimulated emission process, an incoming photon enhances the probability that an excited atomic state will transition to a lower energy state and generate a second photon of the same energy. It is expected, but not experimentally shown, that stimulated emission contributes significantly to the zero resistance current in a superconductor by enhancing the probability that scattered Cooper pairs will return to the macroscopically occupied condensate instead of entering any other state. Here, we use time- and angle-resolved photoemission spectroscopy to study the initial rise of the non-equilibrium quasiparticle population in a Bi2Sr2CaCu2O8+δ cuprate superconductor induced by an ultrashort laser pulse. Our finding reveals significantly slower buildup of quasiparticles in the superconducting state than in the normal state. The slower buildup only occurs when the pump pulse is too weak to deplete the superconducting condensate, and for cuts inside the Fermi arc region. We propose this is a manifestation of stimulated recombination of broken Cooper pairs, and signals an important momentum space dichotomy in the formation of Cooper pairs inside and outside the Fermi arc region.
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Affiliation(s)
- Wentao Zhang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tristan Miller
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Physics, University of California, Berkeley, California 94720, USA
| | - Christopher L Smallwood
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Physics, University of California, Berkeley, California 94720, USA
| | - Yoshiyuki Yoshida
- Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan
| | - Hiroshi Eisaki
- Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan
| | - R A Kaindl
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Dung-Hai Lee
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Physics, University of California, Berkeley, California 94720, USA
| | - Alessandra Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Physics, University of California, Berkeley, California 94720, USA
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22
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Autès G, Isaeva A, Moreschini L, Johannsen JC, Pisoni A, Mori R, Zhang W, Filatova TG, Kuznetsov AN, Forró L, Van den Broek W, Kim Y, Kim KS, Lanzara A, Denlinger JD, Rotenberg E, Bostwick A, Grioni M, Yazyev OV. A novel quasi-one-dimensional topological insulator in bismuth iodide β-Bi4I4. Nat Mater 2016; 15:154-8. [PMID: 26657327 DOI: 10.1038/nmat4488] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 10/13/2015] [Indexed: 05/15/2023]
Abstract
Recent progress in the field of topological states of matter has largely been initiated by the discovery of bismuth and antimony chalcogenide bulk topological insulators (TIs; refs ,,,), followed by closely related ternary compounds and predictions of several weak TIs (refs ,,). However, both the conceptual richness of Z2 classification of TIs as well as their structural and compositional diversity are far from being fully exploited. Here, a new Z2 topological insulator is theoretically predicted and experimentally confirmed in the β-phase of quasi-one-dimensional bismuth iodide Bi4I4. The electronic structure of β-Bi4I4, characterized by Z2 invariants (1;110), is in proximity of both the weak TI phase (0;001) and the trivial insulator phase (0;000). Our angle-resolved photoemission spectroscopy measurements performed on the (001) surface reveal a highly anisotropic band-crossing feature located at the point of the surface Brillouin zone and showing no dispersion with the photon energy, thus being fully consistent with the theoretical prediction.
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Affiliation(s)
- Gabriel Autès
- Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- National Center for Computational Design and Discovery of Novel Materials MARVEL, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Anna Isaeva
- Department of Chemistry and Food Chemistry, TU Dresden, D-01062 Dresden, Germany
| | - Luca Moreschini
- Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jens C Johannsen
- Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Andrea Pisoni
- Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Ryo Mori
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Graduate Group in Applied Science and Technology, University of California, Berkeley, California 94720, USA
| | - Wentao Zhang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Taisia G Filatova
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1-3, GSP-1, 119991 Moscow, Russian Federation
| | - Alexey N Kuznetsov
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1-3, GSP-1, 119991 Moscow, Russian Federation
| | - László Forró
- Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Wouter Van den Broek
- Experimental Physics, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany
| | - Yeongkwan Kim
- Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | - Keun Su Kim
- Departement of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang 790-784, Korea
| | - Alessandra Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Jonathan D Denlinger
- Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Eli Rotenberg
- Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Aaron Bostwick
- Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Marco Grioni
- Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Oleg V Yazyev
- Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- National Center for Computational Design and Discovery of Novel Materials MARVEL, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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23
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Yi M, Wang M, Kemper AF, Mo SK, Hussain Z, Bourret-Courchesne E, Lanzara A, Hashimoto M, Lu DH, Shen ZX, Birgeneau RJ. Bandwidth and Electron Correlation-Tuned Superconductivity in Rb_{0.8}Fe_{2}(Se_{1-z}S_{z})_{2}. Phys Rev Lett 2015; 115:256403. [PMID: 26722933 DOI: 10.1103/physrevlett.115.256403] [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: 03/25/2015] [Indexed: 06/05/2023]
Abstract
We present a systematic angle-resolved photoemission spectroscopy study of the substitution dependence of the electronic structure of Rb_{0.8}Fe_{2}(Se_{1-z}S_{z})_{2} (z=0, 0.5, 1), where superconductivity is continuously suppressed into a metallic phase. Going from the nonsuperconducting Rb_{0.8}Fe_{2}S_{2} to superconducting Rb_{0.8}Fe_{2}Se_{2}, we observe little change of the Fermi surface topology, but a reduction of the overall bandwidth by a factor of 2. Hence, for these heavily electron-doped iron chalcogenides, we have identified electron correlation as explicitly manifested in the quasiparticle bandwidth to be the important tuning parameter for superconductivity, and that moderate correlation is essential to achieving high T_{C}.
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Affiliation(s)
- M Yi
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
| | - Meng Wang
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
| | - A F Kemper
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - S-K Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Z Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - E Bourret-Courchesne
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A Lanzara
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D H Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Z-X Shen
- Stanford Institute of Materials and Energy Sciences, Stanford University, Stanford, California 94305, USA
- Departments of Physics and Applied Physics, and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - R J Birgeneau
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
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24
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25
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Gotlieb K, Hussain Z, Bostwick A, Lanzara A, Jozwiak C. Rapid high-resolution spin- and angle-resolved photoemission spectroscopy with pulsed laser source and time-of-flight spectrometer. Rev Sci Instrum 2013; 84:093904. [PMID: 24089838 DOI: 10.1063/1.4821247] [Citation(s) in RCA: 8] [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] [Indexed: 06/02/2023]
Abstract
A high-efficiency spin- and angle-resolved photoemission spectroscopy (spin-ARPES) spectrometer is coupled with a laboratory-based laser for rapid high-resolution measurements. The spectrometer combines time-of-flight (TOF) energy measurements with low-energy exchange scattering spin polarimetry for high detection efficiencies. Samples are irradiated with fourth harmonic photons generated from a cavity-dumped Ti:sapphire laser that provides high photon flux in a narrow bandwidth, with a pulse timing structure ideally matched to the needs of the TOF spectrometer. The overall efficiency of the combined system results in near-E(F) spin-resolved ARPES measurements with an unprecedented combination of energy resolution and acquisition speed. This allows high-resolution spin measurements with a large number of data points spanning multiple dimensions of interest (energy, momentum, photon polarization, etc.) and thus enables experiments not otherwise possible. The system is demonstrated with spin-resolved energy and momentum mapping of the L-gap Au(111) surface states, a prototypical Rashba system. The successful integration of the spectrometer with the pulsed laser system demonstrates its potential for simultaneous spin- and time-resolved ARPES with pump-probe based measurements.
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Affiliation(s)
- K Gotlieb
- Graduate Group in Applied Science and Technology, University of California, Berkeley, California 94720, USA
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26
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Abstract
The effect of charge-carrier screening on the transport properties of a neutral graphene sheet is studied by directly probing its electronic structure. We find that the Fermi velocity, Dirac point velocity, and overall distortion of the Dirac cone are renormalized due to the screening of the electron-electron interaction in an unusual way. We also observe an increase of the electron mean free path due to the screening of charged impurities. These observations help us to understand the basis for the transport properties of graphene, as well as the fundamental physics of these interesting electron-electron interactions at the Dirac point crossing.
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Affiliation(s)
- David A Siegel
- Department of Physics, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - William Regan
- Department of Physics, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Alexei V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A Zettl
- Department of Physics, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Alessandra Lanzara
- Department of Physics, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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27
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Smallwood CL, Jozwiak C, Zhang W, Lanzara A. An ultrafast angle-resolved photoemission apparatus for measuring complex materials. Rev Sci Instrum 2012; 83:123904. [PMID: 23278002 DOI: 10.1063/1.4772070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We present technical specifications for a high resolution time- and angle-resolved photoemission spectroscopy setup based on a hemispherical electron analyzer and cavity-dumped solid state Ti:sapphire laser used to generate pump and probe beams, respectively, at 1.48 and 5.93 eV. The pulse repetition rate can be tuned from 209 Hz to 54.3 MHz. Under typical operating settings the system has an overall energy resolution of 23 meV, an overall momentum resolution of 0.003 Å(-1), and an overall time resolution of 310 fs. We illustrate the system capabilities with representative data on the cuprate superconductor Bi(2)Sr(2)CaCu(2)O(8+δ). The descriptions and analyses presented here will inform new developments in ultrafast electron spectroscopy.
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28
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Hwang C, Siegel DA, Mo SK, Regan W, Ismach A, Zhang Y, Zettl A, Lanzara A. Fermi velocity engineering in graphene by substrate modification. Sci Rep 2012. [DOI: 10.1038/srep00590] [Citation(s) in RCA: 296] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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29
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Smallwood CL, Hinton JP, Jozwiak C, Zhang W, Koralek JD, Eisaki H, Lee DH, Orenstein J, Lanzara A. Tracking Cooper Pairs in a Cuprate Superconductor by Ultrafast Angle-Resolved Photoemission. Science 2012; 336:1137-9. [DOI: 10.1126/science.1217423] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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30
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Kade A, Kummer K, Vyalikh DV, Danzenbächer S, Blüher A, Mertig M, Lanzara A, Scholl A, Doran A, Molodtsov SL. X-ray Damage in Protein−Metal Hybrid Structures: A Photoemission Electron Microscopy Study. J Phys Chem B 2010; 114:8284-9. [DOI: 10.1021/jp1040585] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Kade
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
| | - K. Kummer
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
| | - D. V. Vyalikh
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
| | - S. Danzenbächer
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
| | - A. Blüher
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
| | - M. Mertig
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
| | - A. Lanzara
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
| | - A. Scholl
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
| | - A. Doran
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Serguei L. Molodtsov
- Institute of Solid State Physics, Technische Universität Dresden, 01062 Dresden, Germany, Institute of Air Handling and Refrigeration Dresden, 01309 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany, Department of Physics, University of California, Berkeley, California 94720, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
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31
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Jozwiak C, Graf J, Lebedev G, Andresen N, Schmid AK, Fedorov AV, El Gabaly F, Wan W, Lanzara A, Hussain Z. A high-efficiency spin-resolved photoemission spectrometer combining time-of-flight spectroscopy with exchange-scattering polarimetry. Rev Sci Instrum 2010; 81:053904. [PMID: 20515152 DOI: 10.1063/1.3427223] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We describe a spin-resolved electron spectrometer capable of uniquely efficient and high energy resolution measurements. Spin analysis is obtained through polarimetry based on low-energy exchange scattering from a ferromagnetic thin-film target. This approach can achieve a similar analyzing power (Sherman function) as state-of-the-art Mott scattering polarimeters, but with as much as 100 times improved efficiency due to increased reflectivity. Performance is further enhanced by integrating the polarimeter into a time-of-flight (TOF) based energy analysis scheme with a precise and flexible electrostatic lens system. The parallel acquisition of a range of electron kinetic energies afforded by the TOF approach results in an order of magnitude (or more) increase in efficiency compared to hemispherical analyzers. The lens system additionally features a 90 degrees bandpass filter, which by removing unwanted parts of the photoelectron distribution allows the TOF technique to be performed at low electron drift energy and high energy resolution within a wide range of experimental parameters. The spectrometer is ideally suited for high-resolution spin- and angle-resolved photoemission spectroscopy (spin-ARPES), and initial results are shown. The TOF approach makes the spectrometer especially ideal for time-resolved spin-ARPES experiments.
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Affiliation(s)
- C Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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32
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Sprinkle M, Siegel D, Hu Y, Hicks J, Tejeda A, Taleb-Ibrahimi A, Le Fèvre P, Bertran F, Vizzini S, Enriquez H, Chiang S, Soukiassian P, Berger C, de Heer WA, Lanzara A, Conrad EH. First direct observation of a nearly ideal graphene band structure. Phys Rev Lett 2009; 103:226803. [PMID: 20366119 DOI: 10.1103/physrevlett.103.226803] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Indexed: 05/29/2023]
Abstract
Angle-resolved photoemission and x-ray diffraction experiments show that multilayer epitaxial graphene grown on the SiC(0001) surface is a new form of carbon that is composed of effectively isolated graphene sheets. The unique rotational stacking of these films causes adjacent graphene layers to electronically decouple leading to a set of nearly independent linearly dispersing bands (Dirac cones) at the graphene K point. Each cone corresponds to an individual macroscale graphene sheet in a multilayer stack where AB-stacked sheets can be considered as low density faults.
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Affiliation(s)
- M Sprinkle
- The Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
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33
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Affiliation(s)
- Z.-X. Shen
- a Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory , Stanford University , California , 94305 , USA
| | - A. Lanzara
- a Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory , Stanford University , California , 94305 , USA
- b Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley , California , 94720 , USA
| | - S. Ishihara
- c Department of Applied Physics , University of Tokyo , Bunkyo-ku, Tokyo , 113-8656 , Japan
| | - N. Nagaosa
- c Department of Applied Physics , University of Tokyo , Bunkyo-ku, Tokyo , 113-8656 , Japan
- d Correlated Electron Research Center, Agency of Industrial Science and Technology , Tsukuba , 305-0046 , Japan
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34
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Zhou SY, Siegel DA, Fedorov AV, Lanzara A. Metal to insulator transition in epitaxial graphene induced by molecular doping. Phys Rev Lett 2008; 101:086402. [PMID: 18764644 DOI: 10.1103/physrevlett.101.086402] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Indexed: 05/26/2023]
Abstract
The capability to control the type and amount of charge carriers in a material and, in the extreme case, the transition from metal to insulator, is one of the key challenges of modern electronics. By employing angle-resolved photoemission spectroscopy we find that a reversible metal to insulator transition and a fine-tuning of the charge carriers from electrons to holes can be achieved in epitaxial bilayer and single layer graphene by molecular doping. The effects of electron screening and disorder are also discussed. These results demonstrate that epitaxial graphene is suitable for electronics applications, as well as provide new opportunities for studying the hole doping regime of the Dirac cone in graphene.
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Affiliation(s)
- S Y Zhou
- Department of Physics, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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35
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Graf J, d'Astuto M, Jozwiak C, Garcia DR, Saini NL, Krisch M, Ikeuchi K, Baron AQR, Eisaki H, Lanzara A. Bond stretching phonon softening and kinks in the angle-resolved photoemission spectra of optimally doped Bi2Sr1.6La0.4Cu2O6+delta superconductors. Phys Rev Lett 2008; 100:227002. [PMID: 18643447 DOI: 10.1103/physrevlett.100.227002] [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: 09/28/2007] [Indexed: 05/26/2023]
Abstract
We report the first measurement of the Cu-O bond stretching phonon dispersion in optimally doped Bi2Sr1.6La0.4Cu2O6+delta using inelastic x-ray scattering. We found a softening of this phonon at q=( approximately 0.25,0,0) from 76 to 60 meV, similar to the one reported in other cuprates. A comparison with angle-resolved photoemission data on the same sample revealed an excellent agreement in terms of energy and momentum between the angle-resolved photoemission nodal kink and the soft part of the bond stretching phonon. Indeed, we find that the momentum space where a 63+/-5 meV kink is observed can be connected with a vector q=(xi,0,0) with xi > or =0.22, corresponding exactly to the soft part of the bond stretching phonon.
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Affiliation(s)
- J Graf
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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36
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Kade A, Vyalikh DV, Danzenbächer S, Kummer K, Blüher A, Mertig M, Lanzara A, Scholl A, Doran A, Molodtsov SL. X-ray Absorption Microscopy of Bacterial Surface Protein Layers: X-ray Damage. J Phys Chem B 2007; 111:13491-8. [DOI: 10.1021/jp073650z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andreas Kade
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
| | - Denis V. Vyalikh
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
| | - Steffen Danzenbächer
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
| | - Kurt Kummer
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
| | - Anja Blüher
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
| | - Michael Mertig
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
| | - Alessandra Lanzara
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
| | - Andreas Scholl
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
| | - Andrew Doran
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
| | - Serguei L. Molodtsov
- Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany, BioNanotechnology and Structure Formation Group, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany, Department of Physics, University of California Berkeley, 366 Le Conte Hall, Berkeley, California 94720-7300, and Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road MS 2R0200, Berkeley, California 94720
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37
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Zhou SY, Gweon GH, Fedorov AV, First PN, de Heer WA, Lee DH, Guinea F, Castro Neto AH, Lanzara A. Substrate-induced bandgap opening in epitaxial graphene. Nat Mater 2007; 6:770-5. [PMID: 17828279 DOI: 10.1038/nmat2003] [Citation(s) in RCA: 575] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 08/07/2007] [Indexed: 05/17/2023]
Abstract
Graphene has shown great application potential as the host material for next-generation electronic devices. However, despite its intriguing properties, one of the biggest hurdles for graphene to be useful as an electronic material is the lack of an energy gap in its electronic spectra. This, for example, prevents the use of graphene in making transistors. Although several proposals have been made to open a gap in graphene's electronic spectra, they all require complex engineering of the graphene layer. Here, we show that when graphene is epitaxially grown on SiC substrate, a gap of approximately 0.26 eV is produced. This gap decreases as the sample thickness increases and eventually approaches zero when the number of layers exceeds four. We propose that the origin of this gap is the breaking of sublattice symmetry owing to the graphene-substrate interaction. We believe that our results highlight a promising direction for bandgap engineering of graphene.
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Affiliation(s)
- S Y Zhou
- Department of Physics, University of California, Berkeley, California 94720, USA
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38
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Garcia DR, Gweon GH, Zhou SY, Graf J, Jozwiak CM, Jung MH, Kwon YS, Lanzara A. Revealing charge density wave formation in the LaTe2 system by angle resolved photoemission spectroscopy. Phys Rev Lett 2007; 98:166403. [PMID: 17501439 DOI: 10.1103/physrevlett.98.166403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Indexed: 05/15/2023]
Abstract
We present the first direct study of charge density wave (CDW) formation in quasi-2D single layer LaTe2 using high-resolution angle resolved photoemission spectroscopy and low energy electron diffraction. CDW formation is driven by Fermi surface (FS) nesting, however, characterized by a surprisingly smaller gap ( approximately 50 meV) than seen in the double layer RTe2 compounds, extending over the entire FS. This establishes LaTe2 as the first reported semiconducting 2D CDW system where the CDW phase is FS nesting driven. In addition, the layer dependence of this phase in the tellurides and the possible transition from a stripe to a checkerboard phase is discussed.
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Affiliation(s)
- D R Garcia
- Department of Physics, University of California, Berkeley, California 94720, USA
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39
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Graf J, Gweon GH, McElroy K, Zhou SY, Jozwiak C, Rotenberg E, Bill A, Sasagawa T, Eisaki H, Uchida S, Takagi H, Lee DH, Lanzara A. Universal high energy anomaly in the angle-resolved photoemission spectra of high temperature superconductors: possible evidence of spinon and holon branches. Phys Rev Lett 2007; 98:067004. [PMID: 17358976 DOI: 10.1103/physrevlett.98.067004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Indexed: 05/14/2023]
Abstract
A universal high energy anomaly in the single particle spectral function is reported in three different families of high temperature superconductors by using angle-resolved photoemission spectroscopy. As we follow the dispersing peak of the spectral function from the Fermi energy to the valence band complex, we find dispersion anomalies marked by two distinctive high energy scales, E1 approximately 0.38 eV and E2 approximately 0.8 eV. E1 marks the energy above which the dispersion splits into two branches. One is a continuation of the near parabolic dispersion, albeit with reduced spectral weight, and reaches the bottom of the band at the Gamma point at approximately 0.5 eV. The other is given by a peak in the momentum space, nearly independent of energy between E1 and E2. Above E2, a bandlike dispersion reemerges. We conjecture that these two energies mark the disintegration of the low-energy quasiparticles into a spinon and holon branch in the high Tc cuprates.
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Affiliation(s)
- J Graf
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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40
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Gweon GH, Zhou SY, Watson MC, Sasagawa T, Takagi H, Lanzara A. Strong and complex electron-lattice correlation in optimally doped Bi2Sr2CaCu2O8+delta. Phys Rev Lett 2006; 97:227001. [PMID: 17155831 DOI: 10.1103/physrevlett.97.227001] [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: 03/31/2005] [Revised: 06/28/2006] [Indexed: 05/12/2023]
Abstract
We discuss the nature of electron-lattice interaction in optimally doped Bi_{2}Sr_{2}CaCu_{2}O_{8+delta} samples, using the isotope effect (IE) in angle resolved photoemission spectroscopy (ARPES) data. The IE in the ARPES linewidth and the IE in the ARPES dispersion are both quite large, implying a strong electron-lattice correlation. The strength of the electron-lattice interaction is "intermediate," i.e., stronger than the Migdal-Eliashberg regime but weaker than the small polaron regime, requiring a more general picture of the ARPES kink than the commonly used Migdal-Eliashberg picture. The two IEs also imply a complex interaction, due to their strong momentum dependence and their differing sign behaviors. In sum, we propose an intermediate-strength coupling of electrons to localized lattice vibrations via charge density fluctuations.
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Affiliation(s)
- G-H Gweon
- Department of Physics, University of California, Berkeley, California 94720, USA
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41
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Finazzi M, Brambilla A, Biagioni P, Graf J, Gweon GH, Scholl A, Lanzara A, Duò L. Interface coupling transition in a thin epitaxial antiferromagnetic film interacting with a ferromagnetic substrate. Phys Rev Lett 2006; 97:097202. [PMID: 17026395 DOI: 10.1103/physrevlett.97.097202] [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: 04/04/2006] [Indexed: 05/12/2023]
Abstract
We report experimental evidence for a transition in the interface coupling between an antiferromagnetic film and a ferromagnetic substrate. The transition is observed in a thin epitaxial NiO film grown on top of Fe(001) as the film thickness is increased. Photoemission electron microscopy excited with linearly polarized x rays shows that the NiO film is antiferromagnetic at room temperature with in-plane uniaxial magnetic anisotropy. The anisotropy axis is perpendicular to the Fe substrate magnetization when the NiO thickness is less than about 15 A, but rapidly becomes parallel to the Fe magnetization for a NiO coverage higher than 25 A.
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Affiliation(s)
- M Finazzi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
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42
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McElroy K, Gweon GH, Zhou SY, Graf J, Uchida S, Eisaki H, Takagi H, Sasagawa T, Lee DH, Lanzara A. Elastic scattering susceptibility of the high temperature superconductor Bi2Sr2CaCu2O(8+delta): a comparison between real and momentum space photoemission spectroscopies. Phys Rev Lett 2006; 96:067005. [PMID: 16606036 DOI: 10.1103/physrevlett.96.067005] [Citation(s) in RCA: 5] [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: 05/09/2005] [Indexed: 05/08/2023]
Abstract
The joint density of states of Bi2Sr2CaCu2O(8+delta) is calculated by evaluating the autocorrelation of the single particle spectral function A(k, omega) measured from angle resolved photoemission spectroscopy (ARPES). These results are compared with Fourier transformed (FT) conductance modulations measured by scanning tunneling microscopy (STM). Good agreement between the two experimental probes is found for two different doping values examined. In addition, by comparing the FT-STM results to the autocorrelated ARPES spectra with different photon polarization, new insight on the form of the STM matrix elements is obtained. This shines new light on unsolved mysteries in the tunneling data.
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Affiliation(s)
- K McElroy
- Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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43
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Gweon GH, Sasagawa T, Zhou SY, Graf J, Takagi H, Lee DH, Lanzara A. An unusual isotope effect in a high-transition-temperature superconductor. Nature 2004; 430:187-90. [PMID: 15241409 DOI: 10.1038/nature02731] [Citation(s) in RCA: 261] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 06/07/2004] [Indexed: 11/09/2022]
Abstract
In conventional superconductors, the electron pairing that allows superconductivity is caused by exchange of virtual phonons, which are quanta of lattice vibration. For high-transition-temperature (high-T(c)) superconductors, it is far from clear that phonons are involved in the pairing at all. For example, the negligible change in T(c) of optimally doped Bi2Sr2CaCu2O8+delta (Bi2212; ref. 1) upon oxygen isotope substitution (16O --> 18O leads to T(c) decreasing from 92 to 91 K) has often been taken to mean that phonons play an insignificant role in this material. Here we provide a detailed comparison of the electron dynamics of Bi2212 samples containing different oxygen isotopes, using angle-resolved photoemission spectroscopy. Our data show definite and strong isotope effects. Surprisingly, the effects mainly appear in broad high-energy humps, commonly referred to as 'incoherent peaks'. As a function of temperature and electron momentum, the magnitude of the isotope effect closely correlates with the superconducting gap--that is, the pair binding energy. We suggest that these results can be explained in a dynamic spin-Peierls picture, where the singlet pairing of electrons and the electron-lattice coupling mutually enhance each other.
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Affiliation(s)
- G-H Gweon
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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44
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Yoshida T, Zhou XJ, Sasagawa T, Yang WL, Bogdanov PV, Lanzara A, Hussain Z, Mizokawa T, Fujimori A, Eisaki H, Shen ZX, Kakeshita T, Uchida S. Metallic behavior of lightly doped La2-xSrxCuO4 with a Fermi surface forming an arc. Phys Rev Lett 2003; 91:027001. [PMID: 12906502 DOI: 10.1103/physrevlett.91.027001] [Citation(s) in RCA: 25] [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: 05/22/2002] [Indexed: 05/24/2023]
Abstract
Lightly doped La2-xSrxCuO4 in the so-called "insulating" spin-glass phase has been studied by angle-resolved photoemission spectroscopy. We have observed that a "quasiparticle" (QP) peak crosses the Fermi level in the node direction of the d-wave superconducting gap, forming an "arc" of Fermi surface, which explains the metallic behavior at high temperatures of the lightly doped materials. The QP spectral weight of the arc smoothly increases with hole doping, which we attribute to the n approximately x behavior of the carrier number in the underdoped and lightly doped regions.
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Affiliation(s)
- T Yoshida
- Department of Physics and Department of Complexity Science and Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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45
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Zhou XJ, Yoshida T, Lanzara A, Bogdanov PV, Kellar SA, Shen KM, Yang WL, Ronning F, Sasagawa T, Kakeshita T, Noda T, Eisaki H, Uchida S, Lin CT, Zhou F, Xiong JW, Ti WX, Zhao ZX, Fujimori A, Hussain Z, Shen ZX. High-temperature superconductors: Universal nodal Fermi velocity. Nature 2003; 423:398. [PMID: 12761537 DOI: 10.1038/423398a] [Citation(s) in RCA: 276] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- X J Zhou
- Department of Physics, Applied Physics and SSRL, Stanford University, Stanford, California 94305, USA.
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46
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Yang WL, Brouet V, Zhou XJ, Choi HJ, Louie SG, Cohen ML, Kellar SA, Bogdanov PV, Lanzara A, Goldoni A, Parmigiani F, Hussain Z, Shen ZX. Band structure and Fermi surface of electron-doped C60 monolayers. Science 2003; 300:303-7. [PMID: 12690192 DOI: 10.1126/science.1082174] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [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
C60 fullerides are challenging systems because both the electron-phonon and electron-electron interactions are large on the energy scale of the expected narrow band width. We report angle-resolved photoemission data on the band dispersion for an alkali-doped C60 monolayer and a detailed comparison with theory. Compared to the maximum bare theoretical band width of 170 meV, the observed 100-meV dispersion is within the range of renormalization by electron-phonon coupling. This dispersion is only a fraction of the integrated peak width, revealing the importance of many-body effects. Additionally, measurements on the Fermi surface indicate the robustness of the Luttinger theorem even for materials with strong interactions.
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Affiliation(s)
- W L Yang
- Advanced Light Source (ALS), Materials Science Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720, USA
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47
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Bogdanov PV, Lanzara A, Zhou XJ, Yang WL, Eisaki H, Hussain Z, Shen ZX. Anomalous momentum dependence of the quasiparticle scattering rate in overdoped Bi2Sr2CaCu2O8. Phys Rev Lett 2002; 89:167002. [PMID: 12398747 DOI: 10.1103/physrevlett.89.167002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2002] [Indexed: 05/24/2023]
Abstract
The question of the anisotropy of the electron scattering in high temperature superconductors is investigated using high resolution angle-resolved photoemission data from Pb-doped Bi2Sr2CaCu2O8 (Bi2212) with suppressed superstructure. The scattering rate of low energy electrons along two bilayer-split pieces of the Fermi surface is measured (via the quasiparticle peak width), and no increase of scattering towards the antinode (pi,0) region is observed, contradicting the expectation from Q=(pi,pi) scattering. The results put a limit on the effects of Q=(pi,pi) scattering on the electronic structure of this overdoped superconductor with still very high T(c).
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Affiliation(s)
- P V Bogdanov
- Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, California 94305, USA
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Lanzara A, Bogdanov PV, Zhou XJ, Kellar SA, Feng DL, Lu ED, Yoshida T, Eisaki H, Fujimori A, Kishio K, Shimoyama JI, Noda T, Uchida S, Hussain Z, Shen ZX. Evidence for ubiquitous strong electron-phonon coupling in high-temperature superconductors. Nature 2001; 412:510-4. [PMID: 11484045 DOI: 10.1038/35087518] [Citation(s) in RCA: 227] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Coupling between electrons and phonons (lattice vibrations) drives the formation of the electron pairs responsible for conventional superconductivity. The lack of direct evidence for electron-phonon coupling in the electron dynamics of the high-transition-temperature superconductors has driven an intensive search for an alternative mechanism. A coupling of an electron with a phonon would result in an abrupt change of its velocity and scattering rate near the phonon energy. Here we use angle-resolved photoemission spectroscopy to probe electron dynamics-velocity and scattering rate-for three different families of copper oxide superconductors. We see in all of these materials an abrupt change of electron velocity at 50-80 meV, which we cannot explain by any known process other than to invoke coupling with the phonons associated with the movement of the oxygen atoms. This suggests that electron-phonon coupling strongly influences the electron dynamics in the high-temperature superconductors, and must therefore be included in any microscopic theory of superconductivity.
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Affiliation(s)
- A Lanzara
- Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA
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Feng DL, Armitage NP, Lu DH, Damascelli A, Hu JP, Bogdanov P, Lanzara A, Ronning F, Shen KM, Eisaki H, Kim C, Shen ZX, Shimoyama J, Kishio K. Bilayer splitting in the electronic structure of heavily overdoped Bi(2)Sr(2)CaCu(2)O(8+delta). Phys Rev Lett 2001; 86:5550-5553. [PMID: 11415298 DOI: 10.1103/physrevlett.86.5550] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2001] [Indexed: 05/23/2023]
Abstract
The electronic structure of heavily overdoped Bi(2)Sr(2)CaCu(2)O(8+delta) is investigated by angle-resolved photoemission spectroscopy. The long-sought bilayer band splitting in this two-plane system is observed in both normal and superconducting states, which qualitatively agrees with the bilayer Hubbard model calculations. The maximum bilayer energy splitting is about 88 meV for the normal state feature, while it is only about 20 meV for the superconducting peak.
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Affiliation(s)
- D L Feng
- Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA
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Zhou XJ, Yoshida T, Kellar SA, Bogdanov PV, Lu ED, Lanzara A, Nakamura M, Noda T, Kakeshita T, Eisaki H, Uchida S, Fujimori A, Hussain Z, Shen ZX. Dual nature of the electronic structure of (La(2--x--y)Nd(y)Sr(x))CuO(4) and La(1.85)Sr(0.15)CuO(4). Phys Rev Lett 2001; 86:5578-5581. [PMID: 11415305 DOI: 10.1103/physrevlett.86.5578] [Citation(s) in RCA: 7] [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: 08/31/2000] [Indexed: 05/23/2023]
Abstract
High resolution angle-resolved photoemission measurements have been carried out on (La(1.4--x)-Nd(0.6)Sr(x))CuO(4), a model system with static one-dimensional (1D) charge ordering (stripe), and (La(1.85)-Sr(0.15))CuO(4), a high temperature superconductor (T(c) = 40 K) with possible dynamic stripes. In addition to the straight segments near ( pi,0) and ( 0,pi) antinodal regions, we have identified the existence of spectral weight along the [1,1] nodal direction in the electronic structure of both systems. This observation of nodal state, together with the straight segments near antinodal regions, reveals the dual nature of the electronic structure of stripes due to the competition of order and disorder.
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Affiliation(s)
- X J Zhou
- Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA
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