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Jat MK, Mishra S, Mann HK, Bajaj R, Watanabe K, Taniguchi T, Krishnamurthy HR, Jain M, Bid A. Controlling Umklapp Scattering in a Bilayer Graphene Moiré Superlattice. NANO LETTERS 2024; 24:2203-2209. [PMID: 38345527 DOI: 10.1021/acs.nanolett.3c04223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
We present experimental findings on electron-electron scattering in two-dimensional moiré heterostructures with a tunable Fermi wave vector, reciprocal lattice vector, and band gap. We achieve this in high-mobility aligned heterostructures of bilayer graphene (BLG) and hBN. Around the half-full point, the primary contribution to the resistance of these devices arises from Umklapp electron-electron (Uee) scattering, making the resistance of graphene/hBN moiré devices significantly larger than that of non-aligned devices (where Uee is forbidden). We find that the strength of Uee scattering follows a universal scaling with Fermi energy and is nonmonotonically dependent on the superlattice period. The Uee scattering can be tuned with the electric field and is affected by layer polarization of BLG. It has a strong particle-hole asymmetry; the resistance when the chemical potential is in the conduction band is significantly lower than when it is in the valence band, making the electron-doped regime more practical for potential applications.
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Affiliation(s)
- Mohit Kumar Jat
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Shubhankar Mishra
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | | | - Robin Bajaj
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - H R Krishnamurthy
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Manish Jain
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Aveek Bid
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
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2
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Pustogow A, Saito Y, Löhle A, Sanz Alonso M, Kawamoto A, Dobrosavljević V, Dressel M, Fratini S. Rise and fall of Landau's quasiparticles while approaching the Mott transition. Nat Commun 2021; 12:1571. [PMID: 33692366 PMCID: PMC7977040 DOI: 10.1038/s41467-021-21741-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/08/2021] [Indexed: 11/09/2022] Open
Abstract
Landau suggested that the low-temperature properties of metals can be understood in terms of long-lived quasiparticles with all complex interactions included in Fermi-liquid parameters, such as the effective mass m⋆. Despite its wide applicability, electronic transport in bad or strange metals and unconventional superconductors is controversially discussed towards a possible collapse of the quasiparticle concept. Here we explore the electrodynamic response of correlated metals at half filling for varying correlation strength upon approaching a Mott insulator. We reveal persistent Fermi-liquid behavior with pronounced quadratic dependences of the optical scattering rate on temperature and frequency, along with a puzzling elastic contribution to relaxation. The strong increase of the resistivity beyond the Ioffe–Regel–Mott limit is accompanied by a ‘displaced Drude peak’ in the optical conductivity. Our results, supported by a theoretical model for the optical response, demonstrate the emergence of a bad metal from resilient quasiparticles that are subject to dynamical localization and dissolve near the Mott transition. Charge transport in strongly correlated electron systems is not fully understood. Here, the authors show that resilient quasiparticles at finite frequency persist into the bad-metal regime near a Mott insulator, where dynamical localization results in a ‘displaced Drude peak’ and strongly enhanced dc resistivity.
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Affiliation(s)
- Andrej Pustogow
- 1. Physikalisches Institut, Universität Stuttgart, 70569, Stuttgart, Germany. .,Department of Physics and Astronomy, UCLA, Los Angeles, CA, USA. .,Institute of Solid State Physics, Vienna University of Technology, Vienna, Austria.
| | - Yohei Saito
- 1. Physikalisches Institut, Universität Stuttgart, 70569, Stuttgart, Germany.,Department of Physics, Graduate School of Science, Hokkaido University, Sapporo, Japan
| | - Anja Löhle
- 1. Physikalisches Institut, Universität Stuttgart, 70569, Stuttgart, Germany
| | - Miriam Sanz Alonso
- 1. Physikalisches Institut, Universität Stuttgart, 70569, Stuttgart, Germany
| | - Atsushi Kawamoto
- Department of Physics, Graduate School of Science, Hokkaido University, Sapporo, Japan
| | - Vladimir Dobrosavljević
- Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | - Martin Dressel
- 1. Physikalisches Institut, Universität Stuttgart, 70569, Stuttgart, Germany.
| | - Simone Fratini
- Institut Néel - CNRS and Université Grenoble Alpes, Grenoble Cedex 9, France.
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3
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Kumar A, Yudson VI, Maslov DL. Quasiparticle and Nonquasiparticle Transport in Doped Quantum Paraelectrics. PHYSICAL REVIEW LETTERS 2021; 126:076601. [PMID: 33666468 DOI: 10.1103/physrevlett.126.076601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 11/16/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Charge transport in doped quantum paraelectrics (QPs) presents a number of puzzles, including a pronounced T^{2} regime in the resistivity. We analyze charge transport in a QP within a model of electrons coupled to a soft transverse optical (TO) mode via a two-phonon mechanism. For T above the soft-mode frequency but below some characteristic scale (E_{0}), the resistivity scales with the occupation number of phonons squared, i.e., as T^{2}. The T^{2} scattering rate does not depend on the carrier number density and is not affected by a crossover between degenerate and nondegenerate regimes, in agreement with the experiment. Temperatures higher than E_{0} correspond to a nonquasiparticle regime, which we analyze by mapping the Dyson equation onto a problem of supersymmetric quantum mechanics. The combination of scattering by two TO phonons and by a longitudinal optical mode explains the data quite well.
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Affiliation(s)
| | - Vladimir I Yudson
- Laboratory for Condensed Matter Physics, National Research University "Higher School of Economics" 20 Myasnitskaya Street, Moscow 101000, Russia
- Russian Quantum Center, Skolkovo, Moscow 143025, Russia
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Bonança MVS, Nazé P, Deffner S. Negative entropy production rates in Drude-Sommerfeld metals. Phys Rev E 2021; 103:012109. [PMID: 33601516 DOI: 10.1103/physreve.103.012109] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/17/2020] [Indexed: 11/07/2022]
Abstract
It is commonly accepted that in typical situations the rate of entropy production is non-negative. We show that this assertion is not entirely correct, not even in the linear regime, if a time-dependent, external perturbation is not compensated by a rapid enough decay of the response function. This is demonstrated for three variants of the Drude model to describe electrical conduction in noble metals, namely the classical free electron gas, the Drude-Sommerfeld model, and the extended Drude-Sommerfeld model. The analysis is concluded with a discussion of potential experimental verifications and ramifications of negative entropy production rates.
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Affiliation(s)
- Marcus V S Bonança
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - Pierre Nazé
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - Sebastian Deffner
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil.,Department of Physics, University of Maryland, Baltimore County, Baltimore, Maryland 21250, USA
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Wang Y, Bossé G, Nair HP, Schreiber NJ, Ruf JP, Cheng B, Adamo C, Shai DE, Lubashevsky Y, Schlom DG, Shen KM, Armitage NP. Subterahertz Momentum Drag and Violation of Matthiessen's Rule in an Ultraclean Ferromagnetic SrRuO_{3} Metallic Thin Film. PHYSICAL REVIEW LETTERS 2020; 125:217401. [PMID: 33274990 DOI: 10.1103/physrevlett.125.217401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 08/14/2020] [Accepted: 10/09/2020] [Indexed: 06/12/2023]
Abstract
SrRuO_{3}, a ferromagnet with an approximately 160 K Curie temperature, exhibits a T^{2}-dependent dc resistivity below ≈30 K. Nevertheless, previous optical studies in the infrared and terahertz range show non-Drude dynamics at low temperatures, which seem to contradict Fermi-liquid predictions. In this work, we measure the low-frequency THz range response of thin films with residual resistivity ratios, ρ_{300K}/ρ_{4K}≈74. At temperatures below 30 K, we find both a sharp zero frequency mode which has a width narrower than k_{B}T/ℏ as well as a broader zero frequency Lorentzian that has at least an order of magnitude larger scattering. Both features have temperature dependences consistent with a Fermi liquid with the wider feature explicitly showing a T^{2} scaling. Above 30 K, there is a crossover to a regime described by a single Drude peak that we believe arises from strong interband electron-electron scattering. Such two channel Drude transport sheds light on reports of the violation of Matthiessen's rule and extreme sensitivity to disorder in metallic ruthenates.
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Affiliation(s)
- Youcheng Wang
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - G Bossé
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
- Physics Department, University of North Florida, Jacksonville, Florida 32224-7699, USA
| | - H P Nair
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - N J Schreiber
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - J P Ruf
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA
| | - B Cheng
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - C Adamo
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - D E Shai
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA
| | - Y Lubashevsky
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - D G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
| | - K M Shen
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
| | - N P Armitage
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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Wang J, Wu J, Wang T, Xu Z, Wu J, Hu W, Ren Z, Liu S, Behnia K, Lin X. T-square resistivity without Umklapp scattering in dilute metallic Bi 2O 2Se. Nat Commun 2020; 11:3846. [PMID: 32737301 PMCID: PMC7395108 DOI: 10.1038/s41467-020-17692-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/14/2020] [Indexed: 11/11/2022] Open
Abstract
Fermi liquids (FLs) display a quadratic temperature (T) dependent resistivity. This can be caused by electron-electron (e-e) scattering in presence of inter-band or Umklapp scattering. However, dilute metallic SrTiO3 was found to display T2 resistivity in absence of either of the two mechanisms. The presence of soft phonons as possible scattering centers raised the suspicion that T2 resistivity is not due to e-e scattering. Here, we present the case of Bi2O2Se, a layered semiconductor with hard phonons, which becomes a dilute metal with a small single-component Fermi surface upon doping. It displays T2 resistivity well below the degeneracy temperature in absence of Umklapp and inter-band scattering. We observe a universal scaling between the T2 resistivity prefactor (A) and the Fermi energy (EF), an extension of the Kadowaki-Woods plot to dilute metals. Our results imply the absence of a satisfactory understanding of the ubiquity of e-e T2 resistivity in FLs. The electrical resistivity of Fermi liquids usually shows square power law with respect to temperature (T2) due to either inter-bandscattering or Umklapp process. Here, authors report T2 resitivity below a temperature where neither Umkapp nor interband scattering is responsible in a dilute metal Bi2O2Se.
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Affiliation(s)
- Jialu Wang
- School of Science, Westlake University, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China
| | - Jing Wu
- School of Science, Westlake University, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China
| | - Tao Wang
- School of Science, Westlake University, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China
| | - Zhuokai Xu
- School of Science, Westlake University, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China
| | - Jifeng Wu
- School of Science, Westlake University, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China
| | - Wanghua Hu
- School of Science, Westlake University, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China
| | - Zhi Ren
- School of Science, Westlake University, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China
| | - Shi Liu
- School of Science, Westlake University, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China
| | - Kamran Behnia
- Laboratoire Physique et Etude de Matériaux (CNRS-Sorbonne Université-ESPCI Paris), PSL Research University, Paris, 75005, France
| | - Xiao Lin
- School of Science, Westlake University, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China. .,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, 310024, Hangzhou, Zhejiang Province, China.
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7
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Kiselev EI, Schmalian J. Lévy Flights and Hydrodynamic Superdiffusion on the Dirac Cone of Graphene. PHYSICAL REVIEW LETTERS 2019; 123:195302. [PMID: 31765178 DOI: 10.1103/physrevlett.123.195302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Indexed: 06/10/2023]
Abstract
We show that the hydrodynamic collision processes of graphene electrons at the neutrality point can be described in terms of a Fokker-Planck equation with a fractional derivative, corresponding to a Lévy flight in momentum space. Thus, electron-electron collisions give rise to frequent small-angle scattering processes that are interrupted by rare large-angle events. The latter give rise to superdiffusive dynamics of collective excitations. We argue that such superdiffusive dynamics is of more general importance to the out-of-equilibrium dynamics of quantum-critical systems.
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Affiliation(s)
- Egor I Kiselev
- Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
| | - Jörg Schmalian
- Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
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8
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Stemmer S, Allen SJ. Non-Fermi liquids in oxide heterostructures. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:062502. [PMID: 29651990 DOI: 10.1088/1361-6633/aabdfa] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Understanding the anomalous transport properties of strongly correlated materials is one of the most formidable challenges in condensed matter physics. For example, one encounters metal-insulator transitions, deviations from Landau Fermi liquid behavior, longitudinal and Hall scattering rate separation, a pseudogap phase, and bad metal behavior. These properties have been studied extensively in bulk materials, such as the unconventional superconductors and heavy fermion systems. Oxide heterostructures have recently emerged as new platforms to probe, control, and understand strong correlation phenomena. This article focuses on unconventional transport phenomena in oxide thin film systems. We use specific systems as examples, namely charge carriers in SrTiO3 layers and interfaces with SrTiO3, and strained rare earth nickelate thin films. While doped SrTiO3 layers appear to be a well behaved, though complex, electron gas or Fermi liquid, the rare earth nickelates are a highly correlated electron system that may be classified as a non-Fermi liquid. We discuss insights into the underlying physics that can be gained from studying the emergence of non-Fermi liquid behavior as a function of the heterostructure parameters. We also discuss the role of lattice symmetry and disorder in phenomena such as metal-insulator transitions in strongly correlated heterostructures.
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Affiliation(s)
- Susanne Stemmer
- Materials Department, University of California, Santa Barbara, CA 93106-5050, United States of America
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9
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Fundamental limits to graphene plasmonics. Nature 2018; 557:530-533. [DOI: 10.1038/s41586-018-0136-9] [Citation(s) in RCA: 323] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 03/26/2018] [Indexed: 11/09/2022]
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