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Dapolito M, Tsuneto M, Zheng W, Wehmeier L, Xu S, Chen X, Sun J, Du Z, Shao Y, Jing R, Zhang S, Bercher A, Dong Y, Halbertal D, Ravindran V, Zhou Z, Petrovic M, Gozar A, Carr GL, Li Q, Kuzmenko AB, Fogler MM, Basov DN, Du X, Liu M. Infrared nano-imaging of Dirac magnetoexcitons in graphene. NATURE NANOTECHNOLOGY 2023; 18:1409-1415. [PMID: 37605044 DOI: 10.1038/s41565-023-01488-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 07/17/2023] [Indexed: 08/23/2023]
Abstract
Magnetic fields can have profound effects on the motion of electrons in quantum materials. Two-dimensional electron systems subject to strong magnetic fields are expected to exhibit quantized Hall conductivity, chiral edge currents and distinctive collective modes referred to as magnetoplasmons and magnetoexcitons. Generating these propagating collective modes in charge-neutral samples and imaging them at their native nanometre length scales have thus far been experimentally elusive. Here we visualize propagating magnetoexciton polaritons at their native length scales and report their magnetic-field-tunable dispersion in near-charge-neutral graphene. Imaging these collective modes and their associated nano-electro-optical responses allows us to identify polariton-modulated optical and photo-thermal electric effects at the sample edges, which are the most pronounced near charge neutrality. Our work is enabled by innovations in cryogenic near-field optical microscopy techniques that allow for the nano-imaging of the near-field responses of two-dimensional materials under magnetic fields up to 7 T. This nano-magneto-optics approach allows us to explore and manipulate magnetopolaritons in specimens with low carrier doping via harnessing high magnetic fields.
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Affiliation(s)
- Michael Dapolito
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, Columbia University, New York, NY, USA
| | - Makoto Tsuneto
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Wenjun Zheng
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Lukas Wehmeier
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - Suheng Xu
- Department of Physics, Columbia University, New York, NY, USA
| | - Xinzhong Chen
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, Columbia University, New York, NY, USA
| | - Jiacheng Sun
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Zengyi Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Yinming Shao
- Department of Physics, Columbia University, New York, NY, USA
| | - Ran Jing
- Department of Physics, Columbia University, New York, NY, USA
| | - Shuai Zhang
- Department of Physics, Columbia University, New York, NY, USA
| | - Adrien Bercher
- Département de Physique de la Matière Quantique, Université de Genève, Genève 4, Switzerland
| | - Yinan Dong
- Department of Physics, Columbia University, New York, NY, USA
| | - Dorri Halbertal
- Department of Physics, Columbia University, New York, NY, USA
| | - Vibhu Ravindran
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Zijian Zhou
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Mila Petrovic
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Adrian Gozar
- Department of Physics, Yale University, New Haven, CT, USA
- Energy Sciences Institute, Yale University, West Haven, CT, USA
| | - G L Carr
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - Qiang Li
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Alexey B Kuzmenko
- Département de Physique de la Matière Quantique, Université de Genève, Genève 4, Switzerland
| | - Michael M Fogler
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - D N Basov
- Department of Physics, Columbia University, New York, NY, USA.
| | - Xu Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA.
| | - Mengkun Liu
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA.
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA.
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Do TN, Shih PH, Gumbs G, Huang D. Engineering plasmon modes and their loss in armchair graphene nanoribbons by selected edge-extended defects. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:485001. [PMID: 34474404 DOI: 10.1088/1361-648x/ac2330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/02/2021] [Indexed: 06/13/2023]
Abstract
The effect of edge modification of armchair graphene nanoribbons (AGNRs) on the collective excitations are theoretically investigated. The tight-binding method is employed in conjunction with the dielectric function. Unconventional plasmon modes and their association with the flat bands of the specially designed AGNRs are thoroughly studied. We demonstrate the robust relationship between the novel collective excitations and both the type and period of the edge modification. Additionally, we reveal that the main features displayed in the (momentum, frequency)-phase diagrams for both single-particle and collective excitations of AGNRs can be efficiently tuned by edge-extended defects. Our obtained plasmon modes are found to be analogous to magnetoplasmons associated with collective excitations of Landau-quantized electrons. This work provides a unique way to engineer discrete magnetoplasmon-like modes of AGNRs in the absence of magnetic field.
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Affiliation(s)
- Thi-Nga Do
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Po-Hsin Shih
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Godfrey Gumbs
- Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, NY 10065, United States of America
| | - Danhong Huang
- US Air Force Research Laboratory, Space Vehicles Directorate (AFRL/RVSU), Kirtland Air Force Base, NM 87117, United States of America
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Nguyen DK, Tran NTT, Chiu YH, Gumbs G, Lin MF. Rich essential properties of Si-doped graphene. Sci Rep 2020; 10:12051. [PMID: 32694799 PMCID: PMC7374172 DOI: 10.1038/s41598-020-68765-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 05/11/2020] [Indexed: 12/02/2022] Open
Abstract
The diverse structural and electronic properties of the Si-adsorbed and -substituted monolayer graphene systems are studied by a complete theoretical framework under the first-principles calculations, including the adatom-diversified geometric structures, the Si- and C-dominated energy bands, the spatial charge densities, variations in the spatial charge densities and the atom- and orbital-projected density of states (DOSs). These critical physical quantities are unified together to display a distinct physical and chemical picture in the studying systems. Under the Si-adsorption and Si-substitution effects, the planar geometric structures are still remained mainly owing to the very strong C–C and Si–C bonds on the honeycomb lattices, respectively. The Si-adsorption cases can create free carriers, while the finite- or zero-gap semiconducting behaviors are revealed in various Si-substitution configurations. The developed theoretical framework can be fully generalized to other emergent layered materials. The Si-doped graphene systems might be a highly promising anode material in the lithium-ion battery owing to its rich potential properties.
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Affiliation(s)
- Duy Khanh Nguyen
- Laboratory of Applied Physics, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam. .,Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
| | - Ngoc Thanh Thuy Tran
- Hierarchical Green-Energy Materials (Hi-GEM) Research Center, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Huang Chiu
- Department of Applied Physics, National Pingtung University, Pingtung, Taiwan.
| | - Godfrey Gumbs
- Department of Physics and Astronomy, Hunter College of the City University of New York, New York, USA
| | - Ming-Fa Lin
- Department of Physics/QTC/Hi-GEM, National Cheng Kung University, Tainan, Taiwan
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Li WB, Lin SY, Tran NTT, Lin MF, Lin KI. Essential geometric and electronic properties in stage- n graphite alkali-metal-intercalation compounds. RSC Adv 2020; 10:23573-23581. [PMID: 35517359 PMCID: PMC9055085 DOI: 10.1039/d0ra00639d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/22/2020] [Indexed: 01/11/2023] Open
Abstract
The rich and unique properties of the stage-n graphite alkali-metal-intercalation compounds are fully investigated by first-principles calculations.
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Affiliation(s)
- Wei-Bang Li
- Department of Physics
- National Cheng Kung University
- Tainan
- Taiwan
| | - Shih-Yang Lin
- Department of Physics
- National Chung Cheng University
- Chiayi
- Taiwan
| | - Ngoc Thanh Thuy Tran
- Hierarchical Green-Energy Materials (Hi-GEM) Research Center
- National Cheng Kung University
- Tainan
- Taiwan
| | - Ming-Fa Lin
- Department of Physics
- National Cheng Kung University
- Tainan
- Taiwan
- Hierarchical Green-Energy Materials (Hi-GEM) Research Center
| | - Kuang-I Lin
- Center for Micro/Nano Science and Technology
- National Cheng Kung University
- Tainan
- Taiwan
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Russell BJ, Zhou B, Taniguchi T, Watanabe K, Henriksen EA. Many-Particle Effects in the Cyclotron Resonance of Encapsulated Monolayer Graphene. PHYSICAL REVIEW LETTERS 2018; 120:047401. [PMID: 29437433 DOI: 10.1103/physrevlett.120.047401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/12/2017] [Indexed: 06/08/2023]
Abstract
We study the infrared cyclotron resonance of high-mobility monolayer graphene encapsulated in hexagonal boron nitride, and simultaneously observe several narrow resonance lines due to interband Landau-level transitions. By holding the magnetic field strength B constant while tuning the carrier density n, we find the transition energies show a pronounced nonmonotonic dependence on the Landau-level filling factor, ν∝n/B. This constitutes direct evidence that electron-electron interactions contribute to the Landau-level transition energies in graphene, beyond the single-particle picture. Additionally, a splitting occurs in transitions to or from the lowest Landau level, which is interpreted as a Dirac mass arising from coupling of the graphene and boron nitride lattices.
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Affiliation(s)
- B Jordan Russell
- Department of Physics, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA
| | - Boyi Zhou
- Department of Physics, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA
| | - T Taniguchi
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0044, Japan
| | - K Watanabe
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0044, Japan
| | - Erik A Henriksen
- Department of Physics, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA
- Institute for Materials Science and Engineering, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA
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Lin CY, Wu JY, Ou YJ, Chiu YH, Lin MF. Magneto-electronic properties of multilayer graphenes. Phys Chem Chem Phys 2015; 17:26008-35. [PMID: 26388455 DOI: 10.1039/c5cp05013h] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This article reviews the rich magneto-electronic properties of multilayer graphene systems. Multilayer graphenes are built from graphene sheets attracting one another by van der Waals forces; the magneto-electronic properties are diversified by the number of layers and the stacking configurations. For an N-layer system, Landau levels are divided into N groups, with each identified by a dominant sublattice associated with the stacking configuration. We focus on the main characteristics of Landau levels, including the degeneracy, wave functions, quantum numbers, onset energies, field-dependent energy spectra, semiconductor-metal transitions, and crossing patterns, which are reflected in the magneto-optical spectroscopy, scanning tunneling spectroscopy, and quantum transport experiments. The Landau levels in AA-stacked graphene are responsible for multiple Dirac cones, while in AB-stacked graphene the Dirac properties depend on the number of graphene layers, and in ABC-stacked graphene the low-lying levels are related to surface states. The Landau-level mixing leads to anticrossings patterns in energy spectra, which are seen for intergroup Landau levels in AB-stacked graphene, while in particular, a formation of both intergroup and intragroup anticrossings is observed in ABC-stacked graphene. The aforementioned magneto-electronic properties lead to diverse optical spectra, plasma spectra, and transport properties when the stacking order and the number of layers are varied. The calculations are in agreement with optical and transport experiments, and novel features that have not yet been verified experimentally are presented.
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Affiliation(s)
- Chiun-Yan Lin
- Department of Physics, National Cheng Kung University, Taiwan.
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7
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Faugeras C, Berciaud S, Leszczynski P, Henni Y, Nogajewski K, Orlita M, Taniguchi T, Watanabe K, Forsythe C, Kim P, Jalil R, Geim AK, Basko DM, Potemski M. Landau level spectroscopy of electron-electron interactions in graphene. PHYSICAL REVIEW LETTERS 2015; 114:126804. [PMID: 25860767 DOI: 10.1103/physrevlett.114.126804] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Indexed: 06/04/2023]
Abstract
We present magneto-Raman scattering studies of electronic inter-Landau level excitations in quasineutral graphene samples with different strengths of Coulomb interaction. The band velocity associated with these excitations is found to depend on the dielectric environment, on the index of Landau level involved, and to vary as a function of the magnetic field. This contradicts the single-particle picture of noninteracting massless Dirac electrons but is accounted for by theory when the effect of electron-electron interaction is taken into account. Raman active, zero-momentum inter-Landau level excitations in graphene are sensitive to electron-electron interactions due to the nonapplicability of the Kohn theorem in this system, with a clearly nonparabolic dispersion relation.
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Affiliation(s)
- C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - S Berciaud
- Institut de Physique et Chimie des Matériaux de Strasbourg and NIE, UMR 7504, Université de Strasbourg and CNRS, BP43, 67034 Strasbourg, Cedex 2, France
| | - P Leszczynski
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - Y Henni
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - K Nogajewski
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - M Orlita
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - T Taniguchi
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - K Watanabe
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Forsythe
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - P Kim
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - R Jalil
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - A K Geim
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - D M Basko
- Université Grenoble 1/CNRS, Laboratoire de Physique et de Modélisation des Milieux Condensés (UMR 5493), B.P. 166, 38042 Grenoble, Cedex 9, France
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
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Abstract
Plasmons in graphene have unusual properties and offer promising prospects for plasmonic applications covering a wide frequency range, ranging from terahertz up to the visible. Plasmon modes have been recently studied in both free-standing and supported graphene. Here, we review plasmons in graphene with particular emphasis on plasmonic excitations in epitaxial graphene and on the influence of the underlying substrate on the screening processes. Although the theoretical comprehension of plasmons in supported graphene is still incomplete, several experimental results provide clues regarding the nature of plasmonic excitations in graphene on metals and semiconductors. Plasmon in graphene can be tuned by chemical doping and gating potentials. We show through selected examples that the adsorbates can be used to tune the plasmon frequency, while the intercalation of chemical species allows the decoupling of the graphene sheet from the substrate to recover the plasmon dispersion of pristine graphene. Finally, we also report intriguing effects due to many-body interaction, such as the excitations generated by electron-electron coupling (magnetoplasmons) and the composite modes arising from the coupling of plasmons with phonons and with charge carriers.
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Affiliation(s)
- Antonio Politano
- Università degli Studi della Calabria, Dipartimento di Fisica, 87036 Rende, CS, Italy.
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