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Bashan N, Tulipman E, Schmalian J, Berg E. Tunable Non-Fermi Liquid Phase from Coupling to Two-Level Systems. PHYSICAL REVIEW LETTERS 2024; 132:236501. [PMID: 38905644 DOI: 10.1103/physrevlett.132.236501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 02/11/2024] [Accepted: 04/25/2024] [Indexed: 06/23/2024]
Abstract
We study a controlled large-N theory of electrons coupled to dynamical two-level systems (TLSs) via spatially random interactions. Such a physical situation arises when electrons scatter off low-energy excitations in a metallic glass, such as a charge or stripe glass. Our theory is governed by a non-Gaussian saddle point, which maps to the celebrated spin-boson model. By tuning the coupling strength we find that the model crosses over from a Fermi liquid at weak coupling to an extended region of non-Fermi liquid behavior at strong coupling, and realizes a marginal Fermi liquid at the crossover. Our results are valid for generic space dimensions d>1.
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Yu Y, Iskakov S, Gull E, Held K, Krien F. Unambiguous Fluctuation Decomposition of the Self-Energy: Pseudogap Physics beyond Spin Fluctuations. PHYSICAL REVIEW LETTERS 2024; 132:216501. [PMID: 38856250 DOI: 10.1103/physrevlett.132.216501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 04/15/2024] [Indexed: 06/11/2024]
Abstract
Correlated electron systems may give rise to multiple effective interactions whose combined impact on quasiparticle properties can be difficult to disentangle. We introduce an unambiguous decomposition of the electronic self-energy which allows us to quantify the contributions of various effective interactions simultaneously. We use this tool to revisit the hole-doped Hubbard model within the dynamical cluster approximation, where commonly spin fluctuations are considered to be the origin of the pseudogap. While our fluctuation decomposition confirms that spin fluctuations indeed suppress antinodal electronic spectral weight, we show that they alone cannot capture the pseudogap self-energy quantitatively. Nonlocal multiboson Feynman diagrams yield substantial contributions and are needed for a quantitative description of the pseudogap.
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Affiliation(s)
- Yang Yu
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Sergei Iskakov
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Emanuel Gull
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Karsten Held
- Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - Friedrich Krien
- Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
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Arpaia R, Martinelli L, Sala MM, Caprara S, Nag A, Brookes NB, Camisa P, Li Q, Gao Q, Zhou X, Garcia-Fernandez M, Zhou KJ, Schierle E, Bauch T, Peng YY, Di Castro C, Grilli M, Lombardi F, Braicovich L, Ghiringhelli G. Signature of quantum criticality in cuprates by charge density fluctuations. Nat Commun 2023; 14:7198. [PMID: 37938250 PMCID: PMC10632404 DOI: 10.1038/s41467-023-42961-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 10/25/2023] [Indexed: 11/09/2023] Open
Abstract
The universality of the strange metal phase in many quantum materials is often attributed to the presence of a quantum critical point (QCP), a zero-temperature phase transition ruled by quantum fluctuations. In cuprates, where superconductivity hinders direct QCP observation, indirect evidence comes from the identification of fluctuations compatible with the strange metal phase. Here we show that the recently discovered charge density fluctuations (CDF) possess the right properties to be associated to a quantum phase transition. Using resonant x-ray scattering, we studied the CDF in two families of cuprate superconductors across a wide doping range (up to p = 0.22). At p* ≈ 0.19, the putative QCP, the CDF intensity peaks, and the characteristic energy Δ is minimum, marking a wedge-shaped region in the phase diagram indicative of a quantum critical behavior, albeit with anomalies. These findings strengthen the role of charge order in explaining strange metal phenomenology and provide insights into high-temperature superconductivity.
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Affiliation(s)
- Riccardo Arpaia
- Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
| | - Leonardo Martinelli
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133, Milano, Italy
| | - Marco Moretti Sala
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133, Milano, Italy
| | - Sergio Caprara
- Dipartimento di Fisica, Università di Roma "La Sapienza", P.le Aldo Moro 5, I-00185, Roma, Italy
- CNR-ISC, via dei Taurini 19, I-00185, Roma, Italy
| | - Abhishek Nag
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - Nicholas B Brookes
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000, Grenoble, France
| | - Pietro Camisa
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133, Milano, Italy
| | - Qizhi Li
- International Center for Quantum Materials, School of Physics, Peking University, CN-100871, Beijing, China
| | - Qiang Gao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, CN-100190, Beijing, China
| | - Xingjiang Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, CN-100190, Beijing, China
| | | | - Ke-Jin Zhou
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - Enrico Schierle
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, D-12489, Berlin, Germany
| | - Thilo Bauch
- Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden
| | - Ying Ying Peng
- International Center for Quantum Materials, School of Physics, Peking University, CN-100871, Beijing, China
| | - Carlo Di Castro
- Dipartimento di Fisica, Università di Roma "La Sapienza", P.le Aldo Moro 5, I-00185, Roma, Italy
| | - Marco Grilli
- Dipartimento di Fisica, Università di Roma "La Sapienza", P.le Aldo Moro 5, I-00185, Roma, Italy
- CNR-ISC, via dei Taurini 19, I-00185, Roma, Italy
| | - Floriana Lombardi
- Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden
| | - Lucio Braicovich
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133, Milano, Italy
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000, Grenoble, France
| | - Giacomo Ghiringhelli
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133, Milano, Italy.
- CNR-SPIN, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133, Milano, Italy.
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Abstract
In traditional metals, the temperature (
T
) dependence of electrical resistivity vanishes at low or high
T
, albeit for different reasons. Here, we review a class of materials, known as “strange” metals, that can violate both of these principles. In strange metals, the change in slope of the resistivity as the mean free path drops below the lattice constant, or as
T
→ 0, can be imperceptible, suggesting continuity between the charge carriers at low and high
T
. We focus on transport and spectroscopic data on candidate strange metals in an effort to isolate and identify a unifying physical principle. Special attention is paid to quantum criticality, Planckian dissipation, Mottness, and whether a new gauge principle is needed to account for the nonlocal transport seen in these materials.
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Affiliation(s)
- Philip W. Phillips
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois, Urbana, IL 61801, USA
| | - Nigel E. Hussey
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, UK
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, 6525 ED Nijmegen, Netherlands
| | - Peter Abbamonte
- Department of Physics, University of Illinois, Urbana, IL 61801, USA
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