Is there a common theme behind the correlated‐electron superconductivity in organic charge‐transfer solids, cobaltates, spinels, and fullerides?

Mazumdar, S.; Clay, R. Torsten

doi:10.1002/pssb.201100723

Cited by 11 publications

(14 citation statements)

References 31 publications

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“…We have recently shown how it may be possible to construct such a framework for the CTS. [51][52][53][54] In this picture, the κ-(ET) 2 X and other dimerized CTS should be described in terms of the underlying 1 4 -filled band as with the other CTS superconductors. 51,52 n the presence of strong dimerization and relatively weak frustration, AFM wins.…”

Section: Discussionmentioning

confidence: 99%

“…Even more interestingly, we have pointed out that there exist several frustrated strongly correlated inorganic 1 4 -filled superconductors that can perhaps be described within the same model. [52][53][54] Finally, the experimental observation of AFM 60 in expanded fullerides A 3 C 60 has led to the modeling of these compounds in terms of a 3D nondegenerate 1 2 -filled band Hubbard model. 61 The threefold degeneracy of the lowest antibonding molecular orbitals in C 60 is removed by Jahn-Teller instability.…”

Section: Discussionmentioning

confidence: 99%

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Absence of long-range superconducting correlations in the frustrated half-filled-band Hubbard model

2012

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We present many-body calculations of superconducting pair-pair correlations in the ground state of the half-filled-band Hubbard model on large anisotropic triangular lattices. Our calculations cover nearly the complete range of anisotropies between the square and isotropic triangular lattice limits. We find that the superconducting pair-pair correlations decrease monotonically with increasing on site Hubbard interaction U for interpair distances greater than nearest neighbor. For the large lattices of interest here the distance dependence of the correlations approaches that for noninteracting electrons. Both these results are consistent with the absence of superconductivity in this model in the thermodynamic limit. We conclude that the effective 1 2 -filled band Hubbard model, suggested by many authors to be appropriate for the κ-(BEDT-TTF)-based organic charge-transfer solids, does not explain the superconducting transition in these materials.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Absence of long-range superconducting correlations in the frustrated half-filled-band Hubbard model

2012

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“…The question that we started with -what is the minimal model that describes the CTS -then continues to be relevant. The only choice appears to be the interacting frustrated 1 4 -filled band model [27], which has the added advantage that it applies equally well to both the dimerized κ-(ET) 2 X and Z[Pd(dmit) 2 ] 2 and the undimerized θ-(ET) 2 X which show CO-SC (as opposed to AFM-SC) transitions (recall that the charge carrier density per molecule is the same in these two classes of CTS). In recent work [28,29] we have shown that a frustrationdriven AFM-spin singlet transition occurs within the dimerized interacting 1 4 -filled band model, where the spin singlet state also exhibits CO.…”

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confidence: 99%

Absence of superconductivity and valence bond order in the Hubbard–Heisenberg model for organic charge-transfer solids

Gomes¹,

Clay²,

Mazumdar³

2013

J. Phys.: Condens. Matter

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A frustrated, effective 1 2 -filled band Hubbard-Heisenberg model has been proposed to describe the strongly dimerized charge-transfer solid families κ-(ET)2X and Z[Pd(dmit)2]2. In addition to unconventional superconductivity these materials also exhibit antiferromagnetism, candidate spinliquid phases, and in the case of Z=EtMe3P, a so-called valence-bond solid phase. We show that neither superconductivity nor the valence-bond solid phase occurs within the Hubbard-Heisenberg model, indicating that the effective 1 2 -filled band model is unsuitable for these materials.PACS numbers: 71.10. Fd, 71.10.Hf, 74.20.Mn, 74.70.Kn Low-dimensional organic charge transfer solids (CTS) are being intensively studied because of their many unusual competing and coexisting electronic phases. The most studied among them are probably the κ-(ET) 2 X and Z[Pd(dmit) 2 ] 2 families, which, depending on the anion X − or cation Z + exhibit unconventional superconductivity (SC), Néel antiferromagnetic (AFM) order, charge ordering (CO), candidate quantum spin liquid (QSL) behavior, and valence-bond solid (VBS) order [1]. The apparent similarity between these with the cuprate superconductors have been noted by many investigators. The semiconductor-SC transition in the CTS occurs under the application of pressure at constant carrier density, which suggests that the transition is driven by a small modification of a particular parameter of an appropriate Hamiltonian. The key questions then are, what is the minimal model, and which is the parameter whose changes give the competing phases.Experimental observations appear to give a simple answer to these questions. The 2:1 (1:2) stoichiometry of semiconductor-paramagnetic metal (PM) transition occurs with increasing frustration. D-wave SC mediated by fluctuations of the AFM ordering at the AFM-PM boundary has been also proposed based on mean-field and dynamic mean-field theories (DMFT) [3][4][5][6][7][8][9][10].Numerical calculations have, however, failed to find SC within the triangular lattice 1 2 -filled band Hubbard model [11][12][13]. Numerical studies have also failed to find a VBS phase in the model [14]. Although the 1 2 -filled Hubbard model on the anisotropic triangular lattice does not appear to support SC, closely related models continue to be suggested as the appropriate theoretical model for describing the SC transition in the CTS. It has been claimed that the simple Hubbard model does not include all the spin-spin interactions that play an important role in the CTS, and that additional spin exchange unrelated to the Hubbard U must be incorporated to correctly capture AFM fluctuation effects [8][9][10]. This has led to theoretical works on the so-called Hubbard-Heisenberg model given below. The goal of this Letter is to critically exam-

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“…Correlated-electron superconductivity (SC) continues to be one of the most challenging problems in condensed matter physics. Even as the large majority of investigators in this research area have focused on cuprates and iron-based superconductors (and more recently, ruthenates), it is now widely recognized that there exist many other unconventional or correlated-electron superconductors, although with lower superconducting critical temperature T c [1][2][3][4][5][6][7][8][9]. Superconducting organic charge-transfer (CT) solids hold a special place in this context, as SC in CT solids was discovered significantly prior to the discovery of the phenomenon in the cuprates [10].…”

Section: Introductionmentioning

confidence: 99%

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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Is there a common theme behind the correlated‐electron superconductivity in organic charge‐transfer solids, cobaltates, spinels, and fullerides?

Cited by 11 publications

References 31 publications

Absence of long-range superconducting correlations in the frustrated half-filled-band Hubbard model

Absence of long-range superconducting correlations in the frustrated half-filled-band Hubbard model

Absence of superconductivity and valence bond order in the Hubbard–Heisenberg model for organic charge-transfer solids

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

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