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Reja S, Nishimoto S. Triplet superconductivity in coupled odd-gon rings. Sci Rep 2019; 9:2691. [PMID: 30804416 PMCID: PMC6389994 DOI: 10.1038/s41598-019-39130-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 01/10/2019] [Indexed: 11/09/2022] Open
Abstract
Shedding light on the nature of spin-triplet superconductivity has been a long-standing quest in condensed matter physics since the discovery of superfluidity in liquid 3He. Nevertheless, the mechanism of spin-triplet pairing is much less understood than that of spin-singlet pairing explained by the Bardeen-Cooper-Schrieffer theory or even observed in high-temperature superconductors. Here we propose a versatile mechanism for spin-triplet superconductivity which emerges through a melting of macroscopic spin polarization stabilized in weakly coupled odd-gon (e.g., triangle, pentagon, etc) systems. We demonstrate the feasibility of sustaining spin-triplet superconductivity with this mechanism by considering a new class of quasi-one-dimensional superconductors A2Cr3As3 (A = K, Rb, and Cs). Furthermore, we suggest a simple effective model to easily illustrate the adaptability of the mechanism to general systems consisting of odd-gon units. This mechanism provides a rare example of superconductivity from on-site Coulomb repulsion.
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Affiliation(s)
- Sahinur Reja
- Department of Physics, Indiana University, Bloomington, Indiana, 47405, USA.
- School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, 4072, Australia.
| | - Satoshi Nishimoto
- Department of Physics, Technical University Dresden, Dresden, 01069, Germany.
- Institute for Theoretical Solid State Physics, IFW Dresden, Dresden, 01069, Germany.
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Fidrysiak M, Zegrodnik M, Spałek J. Realistic estimates of superconducting properties for the cuprates: reciprocal-space diagrammatic expansion combined with variational approach. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:475602. [PMID: 30382027 DOI: 10.1088/1361-648x/aae6fb] [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
We propose a systematic approach to the systems of correlated electrons, the so-called [Formula: see text]-DE-GWF method, based on reciprocal-space ([Formula: see text]-resolved) diagrammatic expansion of the variational Gutzwiller-type wave function for parametrized models of correlated fermions. The present approach, in contrast to either variational Monte-Carlo (VMC), or the recently developed real-space diagrammatic expansion of the Gutzwiller-type wave function (direct-space DE-GWF technique), is applicable directly in the thermodynamic limit and thus is suitable for describing selected singular features of the wave-vector-dependent quantities. We employ the [Formula: see text]-DE-GWF method to extract the non-analytic part of the two leading moments of the fermion spectral-density function across the (two-dimensional) Brillouin zone for the Hubbard model and away from the half-filling. Those moments are used to evaluate the nodal quasiparticle velocities and their spectral weights in the correlated superconducting state. The two velocities determined in that manner exhibit scaling with the electron concentration qualitatively different from that obtained earlier for the excited states of the high-T c cuprates within the projected quasi-particle ansatz, and the results are in a very good quantitative agreement with experimental data if interpreted as those characterizing the spectrum below and above the observed kink. We provide a detailed discussion of the two gaps and two excitation branches (two velocities) appearing naturally within our DE-GWF approach. The two separate sets of characteristics distinguish the renormalized quasiparticle states very close to the Fermi surface from the deeper correlated-state properties. Also, an enhancement of the [Formula: see text]-dependent magnetic susceptibility is shown to contain a spin-fluctuation contribution within our language. Finally, the [Formula: see text]-DE-GWF approach is compared to both the VMC and real-space DE-GWF results for the cases of Hubbard and t-J-U models.
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Affiliation(s)
- M Fidrysiak
- Marian Smoluchowski Institute of Physics, Jagiellonian University, ul. Łojasiewicza 11, 30-348 Kraków, Poland
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Ejima S, Kaneko T, Ohta Y, Fehske H. Order, criticality, and excitations in the extended Falicov-Kimball model. PHYSICAL REVIEW LETTERS 2014; 112:026401. [PMID: 24484030 DOI: 10.1103/physrevlett.112.026401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Indexed: 06/03/2023]
Abstract
Using exact numerical techniques, we investigate the nature of excitonic (electron-hole) bound states and the development of exciton coherence in the one-dimensional half-filled extended Falicov-Kimball model. The ground-state phase diagram of the model exhibits, besides band-insulator and staggered orbital ordered phases, an excitonic insulator (EI) with power-law correlations. The criticality of the EI state shows up in the von Neumann entropy. The anomalous spectral function and condensation amplitude provide the binding energy and coherence length of the electron-hole pairs which, on their part, point towards a Coulomb interaction driven crossover from BCS-like electron-hole pairing fluctuations to tightly bound excitons. We show that while a mass imbalance between electrons and holes does not affect the location of the BCS-BEC crossover regime, it favors staggered orbital ordering to the disadvantage of the EI. Within the Bose-Einstein condensation (BEC) regime, the quasiparticle dispersion develops a flat valence-band top, in accord with the experimental finding for Ta2NiSe5.
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Affiliation(s)
- S Ejima
- Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald, Germany
| | - T Kaneko
- Department of Physics, Chiba University, Chiba 263-8522, Japan
| | - Y Ohta
- Department of Physics, Chiba University, Chiba 263-8522, Japan
| | - H Fehske
- Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald, Germany
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Yunoki S, Dagotto E, Sorella S. Role of strong correlation in the recent angle-resolved photoemission spectroscopy experiments on cuprate superconductors. PHYSICAL REVIEW LETTERS 2005; 94:037001. [PMID: 15698307 DOI: 10.1103/physrevlett.94.037001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Indexed: 05/24/2023]
Abstract
Motivated by recent photoemission experiments on cuprates, the low-lying excitations of a strongly correlated superconducting state are studied numerically. It is observed that along the nodal direction these low-lying one-particle excitations show a linear momentum dependence for a wide range of excitation energies and, thus, they do not present a kinklike structure. The nodal Fermi velocity v(F), as well as other observables, are systematically evaluated directly from the calculated dispersions, and they are found to compare well with experiments. It is argued that the parameter dependence of v(F) is quantitatively explained by a simple picture of a renormalized Fermi velocity.
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Affiliation(s)
- S Yunoki
- Istituto Nazionale per la Fisica della Materia and International School for Advanced Studies, via Beirut 4, 34014 Trieste, Italy
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Poilblanc D, Scalapino DJ, Capponi S. Superconducting gap for a two-leg t-J ladder. PHYSICAL REVIEW LETTERS 2003; 91:137203. [PMID: 14525334 DOI: 10.1103/physrevlett.91.137203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2003] [Indexed: 05/24/2023]
Abstract
Single-particle diagonal and off-diagonal Green's functions of a two-leg t-J ladder at 1/8 doping are investigated by exact diagonalizations techniques. A numerically tractable expression for the superconducting gap is proposed and the frequency dependence of the real and imaginary parts of the gap are determined. The role of the low-energy gapped spin modes, whose energies are computed by a (one-step) contractor renormalization procedure, is discussed.
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Affiliation(s)
- Didier Poilblanc
- Laboratoire de Physique Théorique CNRS-UMR5152, Université Paul Sabatier, F-31062 Toulouse, France
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Fehrenbacher R. Coupling to Optical Phonons in the One-Dimensional t-J Model: Effects on the Superconducting Fluctuations and Phase Separation. PHYSICAL REVIEW LETTERS 1996; 77:2288-2291. [PMID: 10061906 DOI: 10.1103/physrevlett.77.2288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Nazarenko A, Moreo A, Dagotto E, Riera J. dx2-y2 superconductivity in a model of correlated fermions. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R768-R771. [PMID: 9985430 DOI: 10.1103/physrevb.54.r768] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Béal-Monod MT, Maki K. Anisotropic superconductivity: (s+d)-wave model, (d+s)-wave model and the effect of normal impurities. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:5775-5794. [PMID: 9984185 DOI: 10.1103/physrevb.53.5775] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Kuchiev MY, Sushkov OP. Many-body correlation corrections to superconducting pairing in two dimensions. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:443-448. [PMID: 9981997 DOI: 10.1103/physrevb.53.443] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Troyer M, Tsunetsugu H, Rice TM. Properties of lightly doped t-J two-leg ladders. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:251-267. [PMID: 9981971 DOI: 10.1103/physrevb.53.251] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ohta Y, Nakauchi A, Eder R, Tsutsui K, Maekawa S. Excitation spectra of the negative-U Hubbard model: A small-cluster study. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:15617-15620. [PMID: 9980923 DOI: 10.1103/physrevb.52.15617] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Dobry A, Greco A, Koval S, Riera J. Exact diagonalization study of the two-dimensional t-J-Holstein model. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:13722-13725. [PMID: 9980573 DOI: 10.1103/physrevb.52.13722] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Shi Y. Constraints on pairings in the Hubbard model. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:16619-16626. [PMID: 9978665 DOI: 10.1103/physrevb.51.16619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Eder R, Ohta Y. Spin and charge dynamics of the two-dimensional t-J model at intermediate electron densities: Absence of spin-charge separation. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:11683-11689. [PMID: 9977905 DOI: 10.1103/physrevb.51.11683] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Haas S, Dagotto E, Nazarenko A, Riera J. Liaison between superconductivity and phase separation. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:5989-5993. [PMID: 9979514 DOI: 10.1103/physrevb.51.5989] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Dagotto E, Nazarenko A, Moreo A. Antiferromagnetic and van Hove scenarios for the cuprates: Taking the best of both worlds. PHYSICAL REVIEW LETTERS 1995; 74:310-313. [PMID: 10058356 DOI: 10.1103/physrevlett.74.310] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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