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Kuang X, Pantaleón Peralta PA, Angel Silva-Guillén J, Yuan S, Guinea F, Zhan Z. Optical properties and plasmons in moiré structures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:173001. [PMID: 38232397 DOI: 10.1088/1361-648x/ad1f8c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 01/17/2024] [Indexed: 01/19/2024]
Abstract
The discoveries of numerous exciting phenomena in twisted bilayer graphene (TBG) are stimulating significant investigations on moiré structures that possess a tunable moiré potential. Optical response can provide insights into the electronic structures and transport phenomena of non-twisted and twisted moiré structures. In this article, we review both experimental and theoretical studies of optical properties such as optical conductivity, dielectric function, non-linear optical response, and plasmons in moiré structures composed of graphene, hexagonal boron nitride (hBN), and/or transition metal dichalcogenides. Firstly, a comprehensive introduction to the widely employed methodology on optical properties is presented. After, moiré potential induced optical conductivity and plasmons in non-twisted structures are reviewed, such as single layer graphene-hBN, bilayer graphene-hBN and graphene-metal moiré heterostructures. Next, recent investigations of twist-angle dependent optical response and plasmons are addressed in twisted moiré structures. Additionally, we discuss how optical properties and plasmons could contribute to the understanding of the many-body effects and superconductivity observed in moiré structures.
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Affiliation(s)
- Xueheng Kuang
- Yangtze Delta Industrial Innovation Center of Quantum Science and Technology, Suzhou 215000, People's Republic of China
| | | | - Jose Angel Silva-Guillén
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
| | - Shengjun Yuan
- Key Laboratory of Artificial Micro- and Nano-structures of the Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China
- Wuhan Institute of Quantum Technology, Wuhan 430206, People's Republic of China
| | - Francisco Guinea
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
- Donostia International Physics Center, Paseo Manuel de Lardizábal 4, 20018 San Sebastián, Spain
| | - Zhen Zhan
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
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Papaj M, Lewandowski C. Probing correlated states with plasmons. SCIENCE ADVANCES 2023; 9:eadg3262. [PMID: 37126543 DOI: 10.1126/sciadv.adg3262] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Understanding the nature of strongly correlated states in flat-band materials (such as moiré heterostructures) is at the forefront of both experimental and theoretical pursuits. While magnetotransport, scanning probe, and optical techniques are often very successful in investigating the properties of the underlying order, the exact nature of the ground state often remains unknown. Here, we propose to leverage strong light-matter coupling present in the flat-band systems to gain insight through dynamical dielectric response into the structure of the many-body ground state. We argue that because of the enlargement of the effective lattice of the system arising from correlations, conventional long-range plasmon becomes "folded" to yield a multiband plasmon spectrum. We detail several mechanisms through which the structure of the plasmon spectrum and that of the dynamical dielectric response is susceptible to the underlying order, revealing valued insights such as the interaction-driven band gaps, spin-structure, and the order periodicity.
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Affiliation(s)
- Michał Papaj
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Cyprian Lewandowski
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
- Department of Physics, Florida State University, Tallahassee, FL 32306, USA
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Arora A, Rudner MS, Song JCW. Quantum Plasmonic Nonreciprocity in Parity-Violating Magnets. NANO LETTERS 2022; 22:9351-9357. [PMID: 36383645 DOI: 10.1021/acs.nanolett.2c03126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The optical responses of metals are often dominated by plasmonic resonances, that is, the collective oscillations of interacting electron liquids. Here we unveil a new class of plasmons─quantum metric plasmons (QMPs)─that arise in a wide range of parity-violating magnetic metals. In these materials, a dipolar distribution of the quantum metric (a fundamental characteristic of Bloch wave functions) produces intrinsic nonreciprocal bulk plasmons. Strikingly, QMP nonreciprocity manifests even when the single-particle dispersion is symmetric: QMPs are sensitive to time-reversal and parity violations hidden in the Bloch wave function. In materials with asymmetric single-particle dispersions, quantum metric dipole induced nonreciprocity can continue to dominate at large frequencies. We anticipate that QMPs can be realized in a wide range of parity-violating magnets, including twisted bilayer graphene heterostructures, where quantum geometric quantities can achieve large values.
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Affiliation(s)
- Arpit Arora
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore637371
| | - Mark S Rudner
- Department of Physics, University of Washington, SeattleWashington98195, United States
| | - Justin C W Song
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore637371
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Tang G, Zhang L, Zhang Y, Chen J, Chan CT. Near-Field Energy Transfer between Graphene and Magneto-Optic Media. PHYSICAL REVIEW LETTERS 2021; 127:247401. [PMID: 34951812 DOI: 10.1103/physrevlett.127.247401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/19/2021] [Indexed: 06/14/2023]
Abstract
We consider the near-field radiative energy transfer between two separated parallel plates: graphene supported by a substrate and a magneto-optic medium. We first study the scenario in which the two plates have the same temperature. An electric current through the graphene gives rise to nonequilibrium fluctuations and induces energy transfer. Both the magnitude and direction of the energy flux can be controlled by the electric current and an in-plane magnetic field in the magneto-optic medium. This is due to the interplay between the nonreciprocal photon occupation number in the graphene and nonreciprocal surface modes in the magneto-optic plate. Furthermore, we report that a tunable thermoelectric current can be generated in the graphene in the presence of a temperature difference between the two plates.
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Affiliation(s)
- Gaomin Tang
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Lei Zhang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
| | - Yong Zhang
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
- Key Laboratory of Aerospace Thermophysics, Ministry of Industry and Information Technology, Harbin 150001, China
| | - Jun Chen
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Theoretical Physics, Shanxi University, Taiyuan 030006, China
| | - C T Chan
- Department of Physics and Institute for Advanced Study, The Hong Kong University of Science and Technology, Hong Kong, China
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Cao J, Fertig HA, Brey L. Quantum Internal Structure of Plasmons. PHYSICAL REVIEW LETTERS 2021; 127:196403. [PMID: 34797157 DOI: 10.1103/physrevlett.127.196403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
Plasmons are usually described in terms of macroscopic quantities such as electric fields and currents. However, as fundamental excitations of metals, they are also quantum objects with internal structure. We demonstrate that this can induce an intrinsic dipole moment which is tied to the quantum geometry of the Hilbert space of plasmon states. This quantum geometric dipole offers a unique handle for manipulation of plasmon dynamics via density modulations and electric fields. As a concrete example, we demonstrate that scattering of plasmons with a nonvanishing quantum geometric dipole from impurities is nonreciprocal, skewing in different directions in a valley-dependent fashion. This internal structure can be used to control plasmon trajectories in two dimensional materials.
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Affiliation(s)
- Jinlyu Cao
- Department of Physics, Indiana University, Bloomington, Indiana 47405, USA and Quantum Science and Engineering Center, Indiana University, Bloomington, Indiana 47408 USA
| | - H A Fertig
- Department of Physics, Indiana University, Bloomington, Indiana 47405, USA and Quantum Science and Engineering Center, Indiana University, Bloomington, Indiana 47408 USA
| | - Luis Brey
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid, Spain
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Dong Y, Xiong L, Phinney IY, Sun Z, Jing R, McLeod AS, Zhang S, Liu S, Ruta FL, Gao H, Dong Z, Pan R, Edgar JH, Jarillo-Herrero P, Levitov LS, Millis AJ, Fogler MM, Bandurin DA, Basov DN. Fizeau drag in graphene plasmonics. Nature 2021; 594:513-516. [PMID: 34163054 DOI: 10.1038/s41586-021-03640-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 05/12/2021] [Indexed: 11/09/2022]
Abstract
Dragging of light by moving media was predicted by Fresnel1 and verified by Fizeau's celebrated experiments2 with flowing water. This momentous discovery is among the experimental cornerstones of Einstein's special relativity theory and is well understood3,4 in the context of relativistic kinematics. By contrast, experiments on dragging photons by an electron flow in solids are riddled with inconsistencies and have so far eluded agreement with the theory5-7. Here we report on the electron flow dragging surface plasmon polaritons8,9 (SPPs): hybrid quasiparticles of infrared photons and electrons in graphene. The drag is visualized directly through infrared nano-imaging of propagating plasmonic waves in the presence of a high-density current. The polaritons in graphene shorten their wavelength when propagating against the drifting carriers. Unlike the Fizeau effect for light, the SPP drag by electrical currents defies explanation by simple kinematics and is linked to the nonlinear electrodynamics of Dirac electrons in graphene. The observed plasmonic Fizeau drag enables breaking of time-reversal symmetry and reciprocity10 at infrared frequencies without resorting to magnetic fields11,12 or chiral optical pumping13,14. The Fizeau drag also provides a tool with which to study interactions and nonequilibrium effects in electron liquids.
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Affiliation(s)
- Y Dong
- Department of Physics, Columbia University, New York, NY, USA.,Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, USA
| | - L Xiong
- Department of Physics, Columbia University, New York, NY, USA
| | - I Y Phinney
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Z Sun
- Department of Physics, Columbia University, New York, NY, USA
| | - R Jing
- Department of Physics, Columbia University, New York, NY, USA
| | - A S McLeod
- Department of Physics, Columbia University, New York, NY, USA
| | - S Zhang
- Department of Physics, Columbia University, New York, NY, USA
| | - S Liu
- The Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, USA
| | - F L Ruta
- Department of Physics, Columbia University, New York, NY, USA.,Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, USA
| | - H Gao
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Z Dong
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - R Pan
- Department of Physics, Columbia University, New York, NY, USA
| | - J H Edgar
- The Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, USA
| | - P Jarillo-Herrero
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - L S Levitov
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - A J Millis
- Department of Physics, Columbia University, New York, NY, USA
| | - M M Fogler
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - D A Bandurin
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - D N Basov
- Department of Physics, Columbia University, New York, NY, USA.
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