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Active control of micrometer plasmon propagation in suspended graphene. Nat Commun 2022; 13:1465. [PMID: 35304465 PMCID: PMC8933486 DOI: 10.1038/s41467-022-28786-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 01/19/2022] [Indexed: 11/10/2022] Open
Abstract
Due to the two-dimensional character of graphene, the plasmons sustained by this material have been invariably studied in supported samples so far. The substrate provides stability for graphene but often causes undesired interactions (such as dielectric losses, phonon hybridization, and impurity scattering) that compromise the quality and limit the intrinsic flexibility of graphene plasmons. Here, we demonstrate the visualization of plasmons in suspended graphene at room temperature, exhibiting high-quality factor Q~33 and long propagation length > 3 μm. We introduce the graphene suspension height as an effective plasmonic tuning knob that enables in situ change of the dielectric environment and substantially modulates the plasmon wavelength, propagation length, and group velocity. Such active control of micrometer plasmon propagation facilitates near-unity-order modulation of nanoscale energy flow that serves as a plasmonic switch with an on-off ratio above 14. The suspended graphene plasmons possess long propagation length, high tunability, and controllable energy transmission simultaneously, opening up broad horizons for application in nano-photonic devices. Graphene plasmons hold potential for infrared optoelectronic devices, but the interaction with the substrate often degrades their quality. Here, the authors report the characterization of plasmons in suspended graphene with tunable suspension height, showing enhanced quality factors and propagation lengths at room temperature.
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2
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Luo W, Jiang X, Fan J, Zhang N, Cai W, Xu J. Phase-shift-mediated sensitive detection of propagating ultra-confined graphene plasmons. OPTICS EXPRESS 2022; 30:1228-1234. [PMID: 35209287 DOI: 10.1364/oe.444855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
The ultra-confined plasmon field supported by graphene provides an ideal platform for enhanced light-matter interactions and studies of fundamental physical phenomena. On the other hand, the intrinsic ultra-short plasmon wavelength obstructs in-plane detectability of plasmon behaviors, like wavelength variations induced by biomolecule or dragging current. The detection of plasmon wavefront and its spatial shift relies on scattering-type scanning near-field microscopy with a spatial resolution of 20 nm. Here we propose a configuration which can efficiently separate ultra-confined plasmon region from detection region, guaranteeing both field confinement and in-plane sensitive detection of wavelength variations. As an example, the application in detecting Fizeau drag effect is demonstrated. Our study can be applied for detecting strong light-matter interactions, including fundamental physical studies and biosensing applications.
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3
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Wang S, Yoo S, Zhao S, Zhao W, Kahn S, Cui D, Wu F, Jiang L, Utama MIB, Li H, Li S, Zibrov A, Regan E, Wang D, Zhang Z, Watanabe K, Taniguchi T, Zhou C, Wang F. Gate-tunable plasmons in mixed-dimensional van der Waals heterostructures. Nat Commun 2021; 12:5039. [PMID: 34413291 PMCID: PMC8376888 DOI: 10.1038/s41467-021-25269-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 07/14/2021] [Indexed: 11/09/2022] Open
Abstract
Surface plasmons, collective electromagnetic excitations coupled to conduction electron oscillations, enable the manipulation of light-matter interactions at the nanoscale. Plasmon dispersion of metallic structures depends sensitively on their dimensionality and has been intensively studied for fundamental physics as well as applied technologies. Here, we report possible evidence for gate-tunable hybrid plasmons from the dimensionally mixed coupling between one-dimensional (1D) carbon nanotubes and two-dimensional (2D) graphene. In contrast to the carrier density-independent 1D Luttinger liquid plasmons in bare metallic carbon nanotubes, plasmon wavelengths in the 1D-2D heterostructure are modulated by 75% via electrostatic gating while retaining the high figures of merit of 1D plasmons. We propose a theoretical model to describe the electromagnetic interaction between plasmons in nanotubes and graphene, suggesting plasmon hybridization as a possible origin for the observed large plasmon modulation. The mixed-dimensional plasmonic heterostructures may enable diverse designs of tunable plasmonic nanodevices.
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Affiliation(s)
- Sheng Wang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - SeokJae Yoo
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.
- Department of Physics, Korea University, Seoul, Korea.
| | - Sihan Zhao
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Wenyu Zhao
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Salman Kahn
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Dingzhou Cui
- Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA
| | - Fanqi Wu
- Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA
| | - Lili Jiang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - M Iqbal Bakti Utama
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA, USA
| | - Hongyuan Li
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Graduate Group in Applied Science and Technology, University of California at Berkeley, Berkeley, CA, USA
| | - Shaowei Li
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Alexander Zibrov
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Emma Regan
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Graduate Group in Applied Science and Technology, University of California at Berkeley, Berkeley, CA, USA
| | - Danqing Wang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Graduate Group in Applied Science and Technology, University of California at Berkeley, Berkeley, CA, USA
| | - Zuocheng Zhang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Chongwu Zhou
- Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA
- Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Feng Wang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Kavli Energy NanoScience Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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4
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Du G, Bao X, Lin S, Pang H, Bannur Nanjunda S, Bao Q. Infrared Polaritonic Biosensors Based on Two-Dimensional Materials. Molecules 2021; 26:molecules26154651. [PMID: 34361804 PMCID: PMC8347072 DOI: 10.3390/molecules26154651] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/28/2021] [Accepted: 07/28/2021] [Indexed: 11/16/2022] Open
Abstract
In recent years, polaritons in two-dimensional (2D) materials have gained intensive research interests and significant progress due to their extraordinary properties of light-confinement, tunable carrier concentrations by gating and low loss absorption that leads to long polariton lifetimes. With additional advantages of biocompatibility, label-free, chemical identification of biomolecules through their vibrational fingerprints, graphene and related 2D materials can be adapted as excellent platforms for future polaritonic biosensor applications. Extreme spatial light confinement in 2D materials based polaritons supports atto-molar concentration or single molecule detection. In this article, we will review the state-of-the-art infrared polaritonic-based biosensors. We first discuss the concept of polaritons, then the biosensing properties of polaritons on various 2D materials, then lastly the impending applications and future opportunities of infrared polaritonic biosensors for medical and healthcare applications.
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Affiliation(s)
- Guangyu Du
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225009, China; (G.D.); (H.P.)
- Songshan Lake Materials Laboratory, Dongguan 523808, China;
| | - Xiaozhi Bao
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Macau, China;
| | - Shenghuang Lin
- Songshan Lake Materials Laboratory, Dongguan 523808, China;
| | - Huan Pang
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225009, China; (G.D.); (H.P.)
| | - Shivananju Bannur Nanjunda
- Department of Electrical Engineering, Centre of Excellence in Biochemical Sensing and Imaging Technologies (Cen-Bio-SIM), Indian Institute of Technology Madras, Chennai 600036, India
- Correspondence: (S.B.N.); (Q.B.)
| | - Qiaoliang Bao
- Shenzhen Exciton Science and Technology Ltd., Shenzhen 518052, China
- Correspondence: (S.B.N.); (Q.B.)
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5
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Sunku SS, Halbertal D, Engelke R, Yoo H, Finney NR, Curreli N, Ni G, Tan C, McLeod AS, Lo CFB, Dean CR, Hone JC, Kim P, Basov DN. Dual-Gated Graphene Devices for Near-Field Nano-imaging. NANO LETTERS 2021; 21:1688-1693. [PMID: 33586445 DOI: 10.1021/acs.nanolett.0c04494] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Graphene-based heterostructures display a variety of phenomena that are strongly tunable by electrostatic local gates. Monolayer graphene (MLG) exhibits tunable surface plasmon polaritons, as revealed by scanning nano-infrared experiments. In bilayer graphene (BLG), an electronic gap is induced by a perpendicular displacement field. Gapped BLG is predicted to display unusual effects such as plasmon amplification and domain wall plasmons with significantly larger lifetime than MLG. Furthermore, a variety of correlated electronic phases highly sensitive to displacement fields have been observed in twisted graphene structures. However, applying perpendicular displacement fields in nano-infrared experiments has only recently become possible [Li, H.; Nano Lett. 2020, 20, 3106-3112]. In this work, we fully characterize two approaches to realizing nano-optics compatible top gates: bilayer MoS2 and MLG. We perform nano-infrared imaging on both types of structures and evaluate their strengths and weaknesses. Our work paves the way for comprehensive near-field experiments of correlated phenomena and plasmonic effects in graphene-based heterostructures.
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Affiliation(s)
- Sai S Sunku
- Department of Physics, Columbia University, New York, New York 10027, United States
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Dorri Halbertal
- Department of Physics, Columbia University, New York, New York 10027, United States
| | - Rebecca Engelke
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Hyobin Yoo
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Nathan R Finney
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Nicola Curreli
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Guangxin Ni
- Department of Physics, Columbia University, New York, New York 10027, United States
| | - Cheng Tan
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Alexander S McLeod
- Department of Physics, Columbia University, New York, New York 10027, United States
| | - Chiu Fan Bowen Lo
- Department of Physics, Columbia University, New York, New York 10027, United States
| | - Cory R Dean
- Department of Physics, Columbia University, New York, New York 10027, United States
| | - James C Hone
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - D N Basov
- Department of Physics, Columbia University, New York, New York 10027, United States
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6
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Wirth KG, Linnenbank H, Steinle T, Banszerus L, Icking E, Stampfer C, Giessen H, Taubner T. Tunable s-SNOM for Nanoscale Infrared Optical Measurement of Electronic Properties of Bilayer Graphene. ACS PHOTONICS 2021; 8:418-423. [PMID: 33763503 PMCID: PMC7976599 DOI: 10.1021/acsphotonics.0c01442] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Indexed: 05/31/2023]
Abstract
Here we directly probe the electronic properties of bilayer graphene using s-SNOM measurements with a broadly tunable laser source over the energy range from 0.3 to 0.54 eV. We tune an OPO/OPA system around the interband resonance of Bernal stacked bilayer graphene (BLG) and extract amplitude and phase of the scattered light. This enables us to retrieve and reconstruct the complex optical conductivity resonance in BLG around 0.39 eV with nanoscale resolution. Our technique opens the door toward nanoscopic noncontact measurements of the electronic properties in complex hybrid 2D and van der Waals material systems, where scanning tunneling spectroscopy cannot access the decisive layers.
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Affiliation(s)
| | - Heiko Linnenbank
- 4th
Physics Institute and Research Center SCoPE, University of Stuttgart, 70569 Stuttgart, Germany
- SI
Stuttgart Instruments GmbH, 70771 Leinfelden-Echterdingen, Germany
| | - Tobias Steinle
- 4th
Physics Institute and Research Center SCoPE, University of Stuttgart, 70569 Stuttgart, Germany
- SI
Stuttgart Instruments GmbH, 70771 Leinfelden-Echterdingen, Germany
| | - Luca Banszerus
- 2nd
Institute of Physics (IIA), RWTH Aachen
University, 52074 Aachen, Germany
| | - Eike Icking
- 2nd
Institute of Physics (IIA), RWTH Aachen
University, 52074 Aachen, Germany
| | - Christoph Stampfer
- 2nd
Institute of Physics (IIA), RWTH Aachen
University, 52074 Aachen, Germany
- Jülich
Aachen Research Alliance - Fundamentals of Future Information Technology
(JARA-FIT), 52074 Aachen, Germany
| | - Harald Giessen
- 4th
Physics Institute and Research Center SCoPE, University of Stuttgart, 70569 Stuttgart, Germany
- SI
Stuttgart Instruments GmbH, 70771 Leinfelden-Echterdingen, Germany
| | - Thomas Taubner
- I.
Institute of Physics (IA), RWTH Aachen University, 52074 Aachen, Germany
- Jülich
Aachen Research Alliance - Fundamentals of Future Information Technology
(JARA-FIT), 52074 Aachen, Germany
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7
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Sunku SS, McLeod AS, Stauber T, Yoo H, Halbertal D, Ni G, Sternbach A, Jiang BY, Taniguchi T, Watanabe K, Kim P, Fogler MM, Basov DN. Nano-photocurrent Mapping of Local Electronic Structure in Twisted Bilayer Graphene. NANO LETTERS 2020; 20:2958-2964. [PMID: 32052976 DOI: 10.1021/acs.nanolett.9b04637] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report a combined nano-photocurrent and infrared nanoscopy study of twisted bilayer graphene (TBG) enabling access to the local electronic phenomena at length scales as short as 20 nm. We show that the photocurrent changes sign at carrier densities tracking the local superlattice density of states of TBG. We use this property to identify domains of varying local twist angle by local photothermoelectric effect. Consistent with the photocurrent study, infrared nanoimaging experiments reveal optical conductivity features dominated by twist-angle-dependent interband transitions. Our results provide a fast and robust method for mapping the electronic structure of TBG and suggest that similar methods can be broadly applied to probe electronic inhomogeneities of Moiré superlattices in other van der Waals heterostructures.
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Affiliation(s)
- Sai S Sunku
- Department of Physics, Columbia University, New York, New York 10027-6902, United States
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027-6902, United States
| | - Alexander S McLeod
- Department of Physics, Columbia University, New York, New York 10027-6902, United States
| | - Tobias Stauber
- Departamento de Teoría y Simulación de Materiales, Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid 28049, Spain
| | - Hyobin Yoo
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Dorri Halbertal
- Department of Physics, Columbia University, New York, New York 10027-6902, United States
| | - Guangxin Ni
- Department of Physics, Columbia University, New York, New York 10027-6902, United States
| | - Aaron Sternbach
- Department of Physics, Columbia University, New York, New York 10027-6902, United States
| | - Bor-Yuan Jiang
- Department of Physics, UC San Diego, La Jolla, California 92093, United States
| | | | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Michael M Fogler
- Department of Physics, UC San Diego, La Jolla, California 92093, United States
| | - D N Basov
- Department of Physics, Columbia University, New York, New York 10027-6902, United States
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8
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Cheng A, Taniguchi T, Watanabe K, Kim P, Pillet JD. Guiding Dirac Fermions in Graphene with a Carbon Nanotube. PHYSICAL REVIEW LETTERS 2019; 123:216804. [PMID: 31809158 DOI: 10.1103/physrevlett.123.216804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Indexed: 06/10/2023]
Abstract
Relativistic massless charged particles in a two-dimensional conductor can be guided by a one-dimensional electrostatic potential, in an analogous manner to light guided by an optical fiber. We use a carbon nanotube to generate such a guiding potential in graphene and create a single mode electronic waveguide. The nanotube and graphene are separated by a few nanometers and can be controlled and measured independently. As we charge the nanotube, we observe the formation of a single guided mode in graphene that we detect using the same nanotube as a probe. This single electronic guided mode in graphene is sufficiently isolated from other electronic states of linear Dirac spectrum continuum, allowing the transmission of information with minimal distortion.
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Affiliation(s)
- Austin Cheng
- Department of Applied Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | - Kenji Watanabe
- National Institute for Material Science, Tsukuba 305-0044, Japan
| | - Philip Kim
- Department of Applied Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Jean-Damien Pillet
- LSI, CEA/DRF/IRAMIS, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, F-91128 Palaiseau, France
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9
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Hu F, Kim M, Zhang Y, Luan Y, Ho KM, Shi Y, Wang CZ, Wang X, Fei Z. Tailored Plasmons in Pentacene/Graphene Heterostructures with Interlayer Electron Transfer. NANO LETTERS 2019; 19:6058-6064. [PMID: 31398046 DOI: 10.1021/acs.nanolett.9b01945] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
van der Waals (vdW) heterostructures, which are produced by the precise assemblies of varieties of two-dimensional (2D) materials, have demonstrated many novel properties and functionalities. Here we report a nanoplasmonic study of vdW heterostructures that were produced by depositing ordered molecular layers of pentacene on top of graphene. We find through nanoinfrared (IR) imaging that surface plasmons formed due to the collective oscillations of Dirac Fermions in graphene are highly sensitive to the adjacent pentacene layers. In particular, the plasmon wavelength declines systematically but nonlinearly with increasing pentacene thickness. Further analysis and density functional theory (DFT) calculations indicate that the observed peculiar thickness dependence is mainly due to the tunneling-type electron transfer from pentacene to graphene. Our work unveils a new method for tailoring graphene plasmons and deepens our understanding of the intriguing nano-optical phenomena due to interlayer couplings in novel vdW heterostructures.
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Affiliation(s)
- F Hu
- Department of Physics and Astronomy , Iowa State University , Ames , Iowa 50011 , United States
- U.S. DOE Ames Laboratory , Iowa State University , Ames , Iowa 50011 , United States
| | - M Kim
- Department of Physics and Astronomy , Iowa State University , Ames , Iowa 50011 , United States
- U.S. DOE Ames Laboratory , Iowa State University , Ames , Iowa 50011 , United States
| | - Y Zhang
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Y Luan
- Department of Physics and Astronomy , Iowa State University , Ames , Iowa 50011 , United States
- U.S. DOE Ames Laboratory , Iowa State University , Ames , Iowa 50011 , United States
| | - K M Ho
- Department of Physics and Astronomy , Iowa State University , Ames , Iowa 50011 , United States
- U.S. DOE Ames Laboratory , Iowa State University , Ames , Iowa 50011 , United States
| | - Y Shi
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - C Z Wang
- Department of Physics and Astronomy , Iowa State University , Ames , Iowa 50011 , United States
- U.S. DOE Ames Laboratory , Iowa State University , Ames , Iowa 50011 , United States
| | - X Wang
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Z Fei
- Department of Physics and Astronomy , Iowa State University , Ames , Iowa 50011 , United States
- U.S. DOE Ames Laboratory , Iowa State University , Ames , Iowa 50011 , United States
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10
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Sunku SS, Ni GX, Jiang BY, Yoo H, Sternbach A, McLeod AS, Stauber T, Xiong L, Taniguchi T, Watanabe K, Kim P, Fogler MM, Basov DN. Photonic crystals for nano-light in moiré graphene superlattices. Science 2019; 362:1153-1156. [PMID: 30523109 DOI: 10.1126/science.aau5144] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 10/29/2018] [Indexed: 01/16/2023]
Abstract
Graphene is an atomically thin plasmonic medium that supports highly confined plasmon polaritons, or nano-light, with very low loss. Electronic properties of graphene can be drastically altered when it is laid upon another graphene layer, resulting in a moiré superlattice. The relative twist angle between the two layers is a key tuning parameter of the interlayer coupling in thus-obtained twisted bilayer graphene (TBG). We studied the propagation of plasmon polaritons in TBG by infrared nano-imaging. We discovered that the atomic reconstruction occurring at small twist angles transforms the TBG into a natural plasmon photonic crystal for propagating nano-light. This discovery points to a pathway for controlling nano-light by exploiting quantum properties of graphene and other atomically layered van der Waals materials, eliminating the need for arduous top-down nanofabrication.
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Affiliation(s)
- S S Sunku
- Department of Physics, Columbia University, New York, NY 10027, USA.,Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - G X Ni
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - B Y Jiang
- Department of Physics, University of California-San Diego, La Jolla, CA 92093, USA
| | - H Yoo
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - A Sternbach
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - A S McLeod
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - T Stauber
- Departamento de Teoría y Simulación de Materiales, Instituto de Ciencia de Materiales de Madrid, CSIC, E-28049 Madrid, Spain
| | - L Xiong
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - T Taniguchi
- National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
| | - K Watanabe
- National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
| | - P Kim
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - M M Fogler
- Department of Physics, University of California-San Diego, La Jolla, CA 92093, USA
| | - D N Basov
- Department of Physics, Columbia University, New York, NY 10027, USA.
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11
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Frustrated supercritical collapse in tunable charge arrays on graphene. Nat Commun 2019; 10:477. [PMID: 30696830 PMCID: PMC6351629 DOI: 10.1038/s41467-019-08371-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 01/02/2019] [Indexed: 11/09/2022] Open
Abstract
The photon-like behavior of electrons in graphene causes unusual confinement properties that depend strongly on the geometry and strength of the surrounding potential. We report bottom-up synthesis of atomically-precise one-dimensional (1D) arrays of point charges on graphene that allow exploration of a new type of supercritical confinement of graphene carriers. The arrays were synthesized by arranging F4TCNQ molecules into a 1D lattice on back-gated graphene, allowing precise tuning of both the molecular charge and the array periodicity. While dilute arrays of ionized F4TCNQ molecules are seen to behave like isolated subcritical charges, dense arrays show emergent supercriticality. In contrast to compact supercritical clusters, these extended arrays display both supercritical and subcritical characteristics and belong to a new physical regime termed "frustrated supercritical collapse". Here carriers in the far-field are attracted by a supercritical charge distribution, but their fall to the center is frustrated by subcritical potentials in the near-field, similar to trapping of light by a dense cluster of stars in general relativity.
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12
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Wei X, Zhang WJ, Cheng SG. The electronic transport efficiency of a graphene charge carrier guider and an Aharanov-Bohm interferometer. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:485302. [PMID: 30422811 DOI: 10.1088/1361-648x/aae9d3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The electrostatic gating defined channel in graphene forms a charge carrier guider. We theoretically investigated electronic transport properties of a single channel and an Aharanov-Bohm (AB) interferometer, based on a charge carrier guider in a graphene nanoribbon. Quantized conductance is found in a single channel, and the guider shows high efficiency in the optical fiber regime, in good agreement with the experiment results. For an AB interferometer without a magnetic field, quantized conductance occurs when there are a few modes inside the channel. The local density of states (LDOS) inside the AB interferometer shows quantum scars when the scattering is strong. At low magnetic field, a periodical conductance oscillation appears. The conductance has a maximum value at zero magnetic field in the absence of intravalley scattering. The mechanism was investigated by LDOS calculations and a toy model.
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Affiliation(s)
- Xuan Wei
- Department of Physics, Northwest University, Xi'an 710069, People's Republic of China
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13
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Mosallanejad V, Wang K, Qiao Z, Guo G. Perfectly conducting graphene electronic waveguide with curved channels. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:325301. [PMID: 29952314 DOI: 10.1088/1361-648x/aacfca] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We theoretically investigate the electronic transport properties of curved graphene waveguides by employing non-equilibrium Green's function techniques. We systematically study the dependence of the confined waveguide modes on the potential difference, the width of waveguide and side barrier. Through two-terminal electronic transport calculations, we show that the conductance of confined waveguide modes is rather robust against the bending degree of waveguide, in consistence with the band insensitivity to the side barrier. This finding of the perfectly conducting channels strongly suggests the possibility of applying the graphene waveguide in the design of low-power nanoelectronics.
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Affiliation(s)
- Vahid Mosallanejad
- CAS Key Laboratory of Quantum Information, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, People's Republic of China
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Jiang BY, Mele EJ, Fogler MM. Theory of plasmon reflection by a 1D junction. OPTICS EXPRESS 2018; 26:17209-17226. [PMID: 30119535 DOI: 10.1364/oe.26.017209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/28/2018] [Indexed: 06/08/2023]
Abstract
We present a comprehensive study of the reflection of normally incident plasmon waves from a low-conductivity 1D junction in a 2D conductive sheet. Rigorous analytical results are derived in the limits of wide and narrow junctions. Two types of phenomena determine the reflectance, the cavity resonances within the junction and the capacitive coupling between the leads. The resonances give rise to alternating strong and weak reflection but are vulnerable to plasmonic damping. The capacitive coupling, which is immune to damping, induces a near perfect plasmon reflection in junctions narrower than 1/10 of the plasmon wavelength. Our results are important for infrared 2D plasmonic circuits utilizing slot antennas, split gates or nanowire gates. They are also relevant for the implementation of nanoscale terahertz detectors, where optimal light absorption coincides with the maximal junction reflectance.
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Wang D, Fan X, Li X, Dai S, Wei L, Qin W, Wu F, Zhang H, Qi Z, Zeng C, Zhang Z, Hou J. Quantum Control of Graphene Plasmon Excitation and Propagation at Heaviside Potential Steps. NANO LETTERS 2018; 18:1373-1378. [PMID: 29337565 DOI: 10.1021/acs.nanolett.7b05085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Quantum mechanical effects of single particles can affect the collective plasmon behaviors substantially. In this work, the quantum control of plasmon excitation and propagation in graphene is demonstrated by adopting the variable quantum transmission of carriers at Heaviside potential steps as a tuning knob. First, the plasmon reflection is revealed to be tunable within a broad range by varying the ratio γ between the carrier energy and potential height, which originates from the quantum mechanical effect of carrier propagation at potential steps. Moreover, the plasmon excitation by free-space photos can be regulated from fully suppressed to fully launched in graphene potential wells also through adjusting γ, which defines the degrees of the carrier confinement in the potential wells. These discovered quantum plasmon effects offer a unified quantum-mechanical solution toward ultimate control of both plasmon launching and propagating, which are indispensable processes in building plasmon circuitry.
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Affiliation(s)
- Dongli Wang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
- CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Xiaodong Fan
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
- CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Xiaoguang Li
- Institute for Advanced Study, Shenzhen University , Shenzhen, Guangdong 518060, China
| | - Siyuan Dai
- Department of Physics, University of California, San Diego , La Jolla, California 92093, United States
| | - Laiming Wei
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
- CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Wei Qin
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Fei Wu
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
- CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Huayang Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
- CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Zeming Qi
- National Synchrotron Radiation Laboratory, University of Science and Technology of China , Hefei, Anhui 230029, China
| | - Changgan Zeng
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
- CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Zhenyu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Jianguo Hou
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
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Jiang BY, Ni GX, Addison Z, Shi JK, Liu X, Zhao SYF, Kim P, Mele EJ, Basov DN, Fogler MM. Plasmon Reflections by Topological Electronic Boundaries in Bilayer Graphene. NANO LETTERS 2017; 17:7080-7085. [PMID: 28967761 DOI: 10.1021/acs.nanolett.7b03816] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Domain walls separating regions of AB and BA interlayer stacking in bilayer graphene have attracted attention as novel examples of structural solitons, topological electronic boundaries, and nanoscale plasmonic scatterers. We show that strong coupling of domain walls to surface plasmons observed in infrared nanoimaging experiments is due to topological chiral modes confined to the walls. The optical transitions among these chiral modes and the band continua enhance the local conductivity, which leads to plasmon reflection by the domain walls. The imaging reveals two kinds of plasmonic standing-wave interference patterns, which we attribute to shear and tensile domain walls. We compute the electronic structure of both wall varieties and show that the tensile wall contains additional confined bands which produce a structure-specific contrast of the local conductivity, in agreement with the experiment. The coupling between the confined modes and the surface plasmon scattering unveiled in this work is expected to be common to other topological electronic boundaries found in van der Waals materials. This coupling provides a qualitatively new pathway toward controlling plasmons in nanostructures.
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Affiliation(s)
- Bor-Yuan Jiang
- Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Guang-Xin Ni
- Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, People's Republic of China
| | - Zachariah Addison
- Department of Physics & Astronomy, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Jing K Shi
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Xiaomeng Liu
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Shu Yang Frank Zhao
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Philip Kim
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Eugene J Mele
- Department of Physics & Astronomy, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Dimitri N Basov
- Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
- Department of Physics, Columbia University , New York, New York 10027, United States
| | - Michael M Fogler
- Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
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Hartmann RR, Portnoi ME. Two-dimensional Dirac particles in a Pöschl-Teller waveguide. Sci Rep 2017; 7:11599. [PMID: 28912569 PMCID: PMC5599532 DOI: 10.1038/s41598-017-11411-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/23/2017] [Indexed: 11/22/2022] Open
Abstract
We obtain exact solutions to the two-dimensional (2D) Dirac equation for the one-dimensional Pöschl-Teller potential which contains an asymmetry term. The eigenfunctions are expressed in terms of Heun confluent functions, while the eigenvalues are determined via the solutions of a simple transcendental equation. For the symmetric case, the eigenfunctions of the supercritical states are expressed as spheroidal wave functions, and approximate analytical expressions are obtained for the corresponding eigenvalues. A universal condition for any square integrable symmetric potential is obtained for the minimum strength of the potential required to hold a bound state of zero energy. Applications for smooth electron waveguides in 2D Dirac-Weyl systems are discussed.
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Affiliation(s)
- R R Hartmann
- Physics Department, De La Salle University, 2401 Taft Avenue, Manila, 0922, Philippines.
| | - M E Portnoi
- School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom.
- International Institute of Physics, Universidade Federal do Rio Grande do Norte, Natal - RN, Brazil.
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Basov DN, Fogler MM, García de Abajo FJ. Polaritons in van der Waals materials. Science 2017; 354:354/6309/aag1992. [PMID: 27738142 DOI: 10.1126/science.aag1992] [Citation(s) in RCA: 335] [Impact Index Per Article: 47.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- D N Basov
- Department of Physics, University of California, San Diego, CA, USA. Department of Physics, Columbia University, New York, NY, USA.
| | - M M Fogler
- Department of Physics, University of California, San Diego, CA, USA
| | - F J García de Abajo
- Institut de Ciencies Fotoniques, Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain. Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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Fei Z, Foley JJ, Gannett W, Liu MK, Dai S, Ni GX, Zettl A, Fogler MM, Wiederrecht GP, Gray SK, Basov DN. Ultraconfined Plasmonic Hotspots Inside Graphene Nanobubbles. NANO LETTERS 2016; 16:7842-7848. [PMID: 27960518 DOI: 10.1021/acs.nanolett.6b04076] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We report on a nanoinfrared (IR) imaging study of ultraconfined plasmonic hotspots inside graphene nanobubbles formed in graphene/hexagonal boron nitride (hBN) heterostructures. The volume of these plasmonic hotspots is more than one-million-times smaller than what could be achieved by free-space IR photons, and their real-space distributions are controlled by the sizes and shapes of the nanobubbles. Theoretical analysis indicates that the observed plasmonic hotspots are formed due to a significant increase of the local plasmon wavelength in the nanobubble regions. Such an increase is attributed to the high sensitivity of graphene plasmons to its dielectric environment. Our work presents a novel scheme for plasmonic hotspot formation and sheds light on future applications of graphene nanobubbles for plasmon-enhanced IR spectroscopy.
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Affiliation(s)
- Z Fei
- Department of Physics, University of California, San Diego , La Jolla, California 92093, United States
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
- Department of Physics and Astronomy, Iowa State University , Ames, Iowa 50011, United States
| | - J J Foley
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
- Department of Chemistry, William Paterson University , Wayne, New Jersey 07470, United States
| | - W Gannett
- Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - M K Liu
- Department of Physics, University of California, San Diego , La Jolla, California 92093, United States
- Department of Physics and Astronomy, Stony Brook University , Stony Brook, New York 11794, United States
| | - S Dai
- Department of Physics, University of California, San Diego , La Jolla, California 92093, United States
| | - G X Ni
- Department of Physics, University of California, San Diego , La Jolla, California 92093, United States
| | - A Zettl
- Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - M M Fogler
- Department of Physics, University of California, San Diego , La Jolla, California 92093, United States
| | - G P Wiederrecht
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - S K Gray
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - D N Basov
- Department of Physics, University of California, San Diego , La Jolla, California 92093, United States
- Department of Physics, Columbia University , New York, New York 10027, United States
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