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Aydin A, Keski-Rahkonen J, Heller EJ. Quantum acoustics unravels Planckian resistivity. Proc Natl Acad Sci U S A 2024; 121:e2404853121. [PMID: 38968118 PMCID: PMC11253009 DOI: 10.1073/pnas.2404853121] [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: 03/12/2024] [Accepted: 06/05/2024] [Indexed: 07/07/2024] Open
Abstract
Strange metals exhibit universal linear-in-temperature resistivity described by a Planckian scattering rate, the origin of which remains elusive. By employing an approach inspired by quantum optics, we arrive at the coherent state representation of lattice vibrations: quantum acoustics. Utilizing this nonperturbative framework, we demonstrate that lattice vibrations could serve as active drivers in the Planckian resistivity phenomenon, challenging prevailing theories. By treating charge carriers as quantum wave packets negotiating the dynamic acoustic field, we find that a competition ensues between localization and delocalization giving rise to the previously conjectured universal quantum bound of diffusion, [Formula: see text], independent of temperature or any other material parameters. This leads to the enigmatic T-linear resistivity over hundreds of degrees, except at very low temperatures. Quantum diffusion also explains why strange metals have much higher electrical resistivity than typical metals. Our work elucidates the critical role of phonons in Planckian resistivity from a unique perspective and reconsiders their significance in the transport properties of strange metals.
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Affiliation(s)
- Alhun Aydin
- Department of Physics, Harvard University, 02138Cambridge, MA
- Faculty of Engineering and Natural Sciences, Sabanci University, 34956Tuzla, Istanbul, Türkiye
| | - Joonas Keski-Rahkonen
- Department of Physics, Harvard University, 02138Cambridge, MA
- Computational Physics Laboratory, Tampere University, FI-33101Tampere, Finland
| | - Eric J. Heller
- Department of Physics, Harvard University, 02138Cambridge, MA
- Department of Chemistry and Chemical Biology, Harvard University, 02138Cambridge, MA
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Rammal H, Ralko A, Ciuchi S, Fratini S. Transient Localization from the Interaction with Quantum Bosons. PHYSICAL REVIEW LETTERS 2024; 132:266502. [PMID: 38996285 DOI: 10.1103/physrevlett.132.266502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 05/22/2024] [Indexed: 07/14/2024]
Abstract
We carefully revisit the electron-boson scattering problem, going beyond weak-coupling expansions and popular semiclassical treatments. By providing numerically exact results valid at finite temperatures, we demonstrate the existence of a broad regime of electron-boson scattering where quantum localization processes become relevant despite the absence of extrinsic disorder. Localization in the Anderson sense is caused by the dynamical randomness resulting from a large thermal boson population, being, however, effective only at transient times before diffusion can set in. Compelling evidence of this transient localization phenomenon is provided by the observation of a distinctive displaced Drude peak in the optical absorption and the ensuing suppression of conductivity. Our findings identify a general route for anomalous metallic behavior that can broadly apply in interacting quantum matter.
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Keski-Rahkonen J, Ouyang X, Yuan S, Graf AM, Aydin A, Heller EJ. Quantum-Acoustical Drude Peak Shift. PHYSICAL REVIEW LETTERS 2024; 132:186303. [PMID: 38759174 DOI: 10.1103/physrevlett.132.186303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 03/18/2024] [Indexed: 05/19/2024]
Abstract
Quantum acoustics-a recently developed framework parallel to quantum optics-establishes a nonperturbative and coherent treatment of the electron-phonon interaction in real space. The quantum-acoustical representation reveals a displaced Drude peak hiding in plain sight within the venerable Fröhlich model: the optical conductivity exhibits a finite frequency maximum in the far-infrared range and the dc conductivity is suppressed. Our results elucidate the origin of the high-temperature absorption peaks in strange or bad metals, revealing that dynamical lattice disorder steers the system towards a non-Drude behavior.
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Affiliation(s)
- Joonas Keski-Rahkonen
- Department of Physics, Harvard University, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Xiaoyu Ouyang
- Yuanpei College, Peking University, No. 5 Yiheyuan Road, Beijing 100871, China
- School of Physics, Peking University, No. 5 Yiheyuan Road, Beijing 100871, China
| | - Shaobing Yuan
- School of Physics, Peking University, No. 5 Yiheyuan Road, Beijing 100871, China
| | - Anton M Graf
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard, Cambridge, Massachusetts 02138, USA
| | - Alhun Aydin
- Department of Physics, Harvard University, Harvard University, Cambridge, Massachusetts 02138, USA
- Faculty of Engineering and Natural Sciences, Sabanci University, 34956 Tuzla, Istanbul, Türkiye
| | - Eric J Heller
- Department of Physics, Harvard University, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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Karmakar M. Magnetotransport and Fermi surface segmentation in Pauli limited superconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:165601. [PMID: 38190740 DOI: 10.1088/1361-648x/ad1bf6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 01/08/2024] [Indexed: 01/10/2024]
Abstract
We report the first theoretical investigation of the spectroscopic, electrical and optical transport signatures ofd-wave Pauli limited superconductors, based on a non perturbative numerical approach. We demonstrate that the high magnetic field low temperature regime of these materials host a finite momentum paired superconducting phase. Multi-branched dispersion spectra with finite energy superconducting gaps, anisotropic segmentation of the Fermi surface and spatial modulations of the superconducting order characterizes this finite momentum paired phase and should be readily accessible through angle resolved photo emission spectroscopy, quasiparticle interference and differential conductance measurements. Based on the electrical and optical transport properties we capture the non Fermi liquid behavior of these systems at high temperatures, dominated by local superconducting correlations and characterized by resilient quasiparticles which survive the breakdown of the Fermi liquid description. We map out the generic thermal phase diagram of thed-wave Pauli limited superconductors and provide for the first time the accurate estimates of the thermal scales corresponding to the: (a) loss of (quasi) long range superconducting phase coherence (Tc), (b) loss of local pair correlations (Tpg), (c) breakdown of the Fermi liquid theory (Tmax) and cross-over from the non Fermi liquid to the bad metallic phase (TBR). Our thermal phase diagram mapped out on the basis of the spectroscopic and transport properties are found to be in qualitative agreement with the experimental observations on CeCoIn5andκ-BEDT, in terms of the thermodynamic phases and the phase transitions. The results presented in this paper are expected to initiate important transport and spectroscopic experiments on the Pauli limitedd-wave superconductors, providing sharp signatures of the finite momentum Cooper paired state in these materials.
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Affiliation(s)
- Madhuparna Karmakar
- Department of Physics and Nanotechnology, College of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Chennai, 603203, India
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Pustogow A, Kawasugi Y, Sakurakoji H, Tajima N. Chasing the spin gap through the phase diagram of a frustrated Mott insulator. Nat Commun 2023; 14:1960. [PMID: 37029139 PMCID: PMC10082190 DOI: 10.1038/s41467-023-37491-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 03/16/2023] [Indexed: 04/09/2023] Open
Abstract
The quest for entangled spin excitations has stimulated intense research on frustrated magnetic systems. For almost two decades, the triangular-lattice Mott insulator κ-(BEDT-TTF)2Cu2(CN)3 has been one of the hottest candidates for a gapless quantum spin liquid with itinerant spinons. Very recently, however, this scenario was overturned as electron-spin-resonance (ESR) studies unveiled a spin gap, calling for reevaluation of the magnetic ground state. Here we achieve a precise mapping of this spin-gapped phase through the Mott transition by ultrahigh-resolution strain tuning. Our transport experiments reveal a reentrance of charge localization below T⋆ = 6 K associated with a gap size of 30-50 K. The negative slope of the insulator-metal boundary, dT⋆/dp < 0, evidences the low-entropy nature of the spin-singlet ground state. By tuning the enigmatic '6K anomaly' through the phase diagram of κ-(BEDT-TTF)2Cu2(CN)3, we identify it as the transition to a valence-bond-solid phase, in agreement with previous thermal expansion and magnetic resonance studies. This spin-gapped insulating state persists at T → 0 until unconventional superconductivity and metallic transport proliferate.
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Affiliation(s)
- A Pustogow
- Institute of Solid State Physics, TU Wien, 1040, Vienna, Austria.
| | - Y Kawasugi
- Department of Physics, Toho University, Funabashi, 274-8510, Chiba, Japan
- Condensed Molecular Materials Laboratory, RIKEN, Wako, Saitama, 351-0198, Japan
| | - H Sakurakoji
- Department of Physics, Toho University, Funabashi, 274-8510, Chiba, Japan
| | - N Tajima
- Department of Physics, Toho University, Funabashi, 274-8510, Chiba, Japan
- Condensed Molecular Materials Laboratory, RIKEN, Wako, Saitama, 351-0198, Japan
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How to Recognize the Universal Aspects of Mott Criticality? CRYSTALS 2022. [DOI: 10.3390/cryst12070932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this paper we critically discuss several examples of two-dimensional electronic systems displaying interaction-driven metal-insulator transitions of the Mott (or Wigner–Mott) type, including dilute two-dimension electron gases (2DEG) in semiconductors, Mott organic materials, as well as the recently discovered transition-metal dichalcogenide (TMD) moiré bilayers. Remarkably similar behavior is found in all these systems, which is starting to paint a robust picture of Mott criticality. Most notable, on the metallic side a resistivity maximum is observed whose temperature scale vanishes at the transition. We compare the available experimental data on these systems to three existing theoretical scenarios: spinon theory, Dynamical Mean Field Theory (DMFT) and percolation theory. We show that the DMFT and percolation pictures for Mott criticality can be distinguished by studying the origins of the resistivity maxima using an analysis of the dielectric response.
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Abstract
In the quasi-one-dimensional (TMTTF)2X compounds with effectively quarter-filled bands, electronic charge order is stabilized from the delicate interplay of Coulomb repulsion and electronic bandwidth. The correlation strength is commonly tuned by physical pressure or chemical substitution with stoichiometric ratios of anions and cations. Here, we investigate the charge-ordered state through partial substitution of the anions in (TMTTF)2[AsF6]1−x[SbF6]x with x≈0.3, determined from the intensity of infrared vibrations, which is sufficient to suppress the spin-Peierls state. Our dc transport experiments reveal a transition temperature TCO = 120 K and charge gap ΔCO=430 K between the values of the two parent compounds (TMTTF)2AsF6 and (TMTTF)2SbF6. Upon plotting the two parameters for different (TMTTF)2X, we find a universal relationship between TCO and ΔCO yielding that the energy gap vanishes for transition temperatures TCO≤60 K. While these quantities indicate that the macroscopic correlation strength is continuously tuned, our vibrational spectroscopy results probing the local charge disproportionation suggest that 2δ is modulated on a microscopic level.
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Pressure-Tuned Superconducting Dome in Chemically-Substituted κ-(BEDT-TTF)2Cu2(CN)3. CRYSTALS 2021. [DOI: 10.3390/cryst11070817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The quantum spin liquid candidate κ-(BEDT-TTF)2Cu2(CN)3 has been established as the prime example of a genuine Mott insulator that can be tuned across the first-order insulator–metal transition either by chemical substitution or by physical pressure. Here, we explore the superconducting state that occurs at low temperatures, when both methods are combined, i.e., when κ-[(BEDT-TTF)1−x(BEDT-STF)x]2Cu2(CN)3 is pressurized. We discovered superconductivity for partial BEDT-STF substitution with x = 0.10–0.12 even at ambient pressure, i.e., a superconducting state is realized in the range between a metal and a Mott insulator without magnetic order. Furthermore, we observed the formation of a superconducting dome by pressurizing the substituted crystals; we assigned this novel behavior to disorder emanating from chemical tuning.
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