Coulomb enhancement of superconducting pair-pair correlations in a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mfrac><mml:mn>3</mml:mn><mml:mn>4</mml:mn></mml:mfrac></mml:math>-filled model for<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>κ</mml:mi><mml:mtext>−</mml:mtext><mml:mo>(</mml:mo><mml:mtext>BEDT-TTF</mml:mtext><mml:mo>)</mml:mo><mml:mrow><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub><mml:mi>X</mml:mi></mml:mrow></mml:math>

Silva, W. Wasanthi De; Gomes, Niladri; Mazumdar, S.; Clay, R. Torsten

doi:10.1103/physrevb.93.205111

Cited by 17 publications

(20 citation statements)

References 101 publications

(175 reference statements)

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“…In all lattices we find that as a function of λ,P reaches a broad peak at an intermediate value of λ before beginning to decrease. A similar broad maximum inP is seen as a function of U in zero temperature λ = 0 calculations at ρ = 0.5 [16,17]. We expect the decrease inP at larger λ and/or U is caused by the increasing effective mass of pairs.…”

supporting

confidence: 56%

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Superconductivity due to cooperation of electron-electron and electron-phonon interactions at quarter filling

Clay

Roy

2020

Phys. Rev. Research

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We present the results of Quantum Monte Carlo calculations for a two dimensional frustrated Hubbard model coupled to bond phonons. The model is known to have a d-wave superconducting ground state in the limit of large phonon frequency for sufficiently strong electron-phonon coupling. In the absence of electron-phonon coupling the Hubbard interaction U enhances superconducting pairing in the quarter-filled (density ρ = 0.5) band. We show here that at ρ = 0.5 electron-electron and electron-phonon interactions cooperatively reinforce d-wave pairing, while competing with each other at all other densities. Cooperative degrees of freedom are found in many phase transitions and are essential to understanding superconductivity in strongly correlated materials.

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confidence: 56%

“…4) is very different from ρ = 1. At ρ ∼ 0.5 zero-temperature calculations find thatP increases with U [15][16][17]. Here, for all the lattices we find thatP increases with increasing U and λ at the same densities where T = 0 calculations find enhancement by U alone.…”

supporting

confidence: 51%

Superconductivity due to cooperation of electron-electron and electron-phonon interactions at quarter filling

Clay

Roy

2020

Phys. Rev. Research

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“…In addition, the existence of a dipolar spin-liquid phase has been suggested [29,30] (possibly also explaining the dielectric anomaly in κ-(ET) 2 Cu 2 (CN) 3 [31]). Furthermore, the two-orbital Hubbard model has been claimed to be relevant for the description of superconductivity in charge-transfer salts [32][33][34][35], including its proximity to charge-ordered phases [36,37]. In addition, spin and charge fluctuations near the metal-insulator transition in multiorbital models have been analyzed [38].…”

Section: Introductionmentioning

confidence: 99%

Charge orders in organic charge-transfer salts

et al. 2017

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Motivated by recent experimental suggestions of charge-order-driven ferroelectricity in organic charge-transfer salts, such as κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Cl, we investigate magnetic and charge-ordered phases that emerge in an extended twoorbital Hubbard model on the anisotropic triangular lattice at 3/4 filling. This model takes into account the presence of two organic BEDT-TTF molecules, which form a dimer on each site of the lattice, and includes short-range intramolecular and intermolecular interactions and hoppings. By using variational wave functions and quantum Monte Carlo techniques, we find two polar states with charge disproportionation inside the dimer, hinting to ferroelectricity. These charge-ordered insulating phases are stabilized in the strongly correlated limit and their actual charge pattern is determined by the relative strength of intradimer to interdimer couplings. Our results suggest that ferroelectricity is not driven by magnetism, since these polar phases can be stabilized also without antiferromagnetic order and provide a possible microscopic explanation of the experimental observations. In addition, a conventional dimer-Mott state (with uniform density and antiferromagnetic order) and a nonpolar charge-ordered state (with charge-rich and charge-poor dimers forming a checkerboard pattern) can be stabilized in the strong-coupling regime. Finally, when electron-electron interactions are weak, metallic states appear, with either uniform charge distribution or a peculiar 12-site periodicity that generates honeycomb-like charge order.

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“…Pressure increases frustration, causing the spin singlets to be mobile. Calculations on an anisotropic triangular lattice [41] as well as on κ-lattices [42,57] have indeed found that superconducting pair correlations are enhanced by the Hubbard U uniquely at 1 4 -filling. DMRG calculations on a width-three triangular lattice found evidence for p-wave and d-wave SC in the density range 0.40∼0.65 [58], which would appear to agree with the conclusion from the previous work [41].…”

Section: Discussionmentioning

confidence: 93%

Absence of Superconductivity in the Hubbard Dimer Model for κ-(BEDT-TTF)2X

2021

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In the most studied family of organic superconductors κ-(BEDT-TTF)2X, the BEDT-TTF molecules that make up the conducting planes are coupled as dimers. For some anions X, an antiferromagnetic insulator is found at low temperatures adjacent to superconductivity. With an average of one hole carrier per dimer, the BEDT-TTF band is effectively 12-filled. Numerous theories have suggested that fluctuations of the magnetic order can drive superconducting pairing in these models, even as direct calculations of superconducting pairing in monomer 12-filled band models find no superconductivity. Here, we present accurate zero-temperature Density Matrix Renormalization Group (DMRG) calculations of a dimerized lattice with one hole per dimer. While we do find an antiferromagnetic state in our results, we find no evidence for superconducting pairing. This further demonstrates that magnetic fluctuations in the effective 12-filled band approach do not drive superconductivity in these and related materials.

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Coulomb enhancement of superconducting pair-pair correlations in a34-filled model forκ−(BEDT-TTF)2X

Cited by 17 publications

References 101 publications

Superconductivity due to cooperation of electron-electron and electron-phonon interactions at quarter filling

Superconductivity due to cooperation of electron-electron and electron-phonon interactions at quarter filling

Charge orders in organic charge-transfer salts

Absence of Superconductivity in the Hubbard Dimer Model for κ-(BEDT-TTF)2X

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