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Gomes N, Clay RT, Mazumdar S. Absence of superconductivity and valence bond order in the Hubbard-Heisenberg model for organic charge-transfer solids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:385603. [PMID: 23995074 DOI: 10.1088/0953-8984/25/38/385603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A frustrated, effective ½-filled band Hubbard-Heisenberg model has been proposed for describing the strongly dimerized charge-transfer solid families κ-(ET)2X and Z[Pd(dmit)2]2. In addition to showing unconventional superconductivity, these materials also exhibit antiferromagnetism, candidate spin-liquid phases, and, in the case of Z=EtMe3P, a spin-gapped phase that has sometimes been referred to as a valence bond solid. We show that neither superconductivity nor the valence bond order phase occurs within the Hubbard-Heisenberg model. We suggest that a description based on ¼-filling, that is reached when the carrier concentration per molecule instead of per dimer is considered, thus may be appropriate.
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Affiliation(s)
- N Gomes
- Department of Physics, University of Arizona, Tucson, AZ 85721, USA
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Scriven EP, Powell BJ. Geometrical frustration in the spin liquid β'-Me3EtSb[Pd(dmit)2]2 and the valence-bond solid Me3EtP[Pd(dmit)2]2. PHYSICAL REVIEW LETTERS 2012; 109:097206. [PMID: 23002879 DOI: 10.1103/physrevlett.109.097206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 04/02/2012] [Indexed: 06/01/2023]
Abstract
We show that the electronic structures of the title compounds predicted by density functional theory are well described by tight binding models. We determine the frustration ratio, J'/J, of the Heisenberg model on the anisotropic triangular lattice, which describes the spin degrees of freedom in the Mott insulating phase for a range of Pd(dmit)2 salts. All of the antiferromagnetic materials studied have J'/J is < or approximately equal to 0.5 or J'/J > or approximately equal to 0.9, and all salts with 0.5 < or approximately equal to J'/J < or approximately equal to 0.9 are known, experimentally, to be charge ordered valence-bond solids or spin liquids.
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Affiliation(s)
- E P Scriven
- Centre for Organic Photonics and Electronics, School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072, Australia
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Scriven E, Powell BJ. Toward the parametrization of the Hubbard model for salts of bis(ethylenedithio)tetrathiafulvalene: A density functional study of isolated molecules. J Chem Phys 2009; 130:104508. [DOI: 10.1063/1.3080543] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Chen WQ, Yang KY, Zhou Y, Zhang FC. Strong coupling theory for superconducting iron pnictides. PHYSICAL REVIEW LETTERS 2009; 102:047006. [PMID: 19257468 DOI: 10.1103/physrevlett.102.047006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Indexed: 05/27/2023]
Abstract
Superconductivity in iron pnictides is studied by using a two-orbital Hubbard model in the large U limit. The Coulomb repulsion induces an orbital-dependent pairing between charge carriers. The pairing is found mainly from the scattering within the same Fermi pocket. The interpocket pair scatterings determine the symmetry of the superconductivity, which is extended s wave at small Hund's coupling, and d wave at large Hund's coupling and large U. The former is consistent with recent experiments of angle-resolved photoemission spectroscopy and Andreev reflection spectroscopy.
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Affiliation(s)
- Wei-Qiang Chen
- Department of Physics, the University of Hong Kong, Hong Kong, China
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Clay RT, Li H, Mazumdar S. Absence of superconductivity in the half-filled band Hubbard model on the anisotropic triangular lattice. PHYSICAL REVIEW LETTERS 2008; 101:166403. [PMID: 18999691 DOI: 10.1103/physrevlett.101.166403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Indexed: 05/27/2023]
Abstract
We report exact calculations of magnetic and superconducting pair-pair correlations for the half-filled band Hubbard model on an anisotropic triangular lattice. Our results for the magnetic phases are similar to those obtained with other techniques. The superconducting pair-pair correlations at distances beyond nearest neighbor decrease monotonically with increasing Hubbard interaction U for all anisotropy, indicating the absence of frustration-driven superconductivity within the model.
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Affiliation(s)
- R T Clay
- Department of Physics and Astronomy and HPC2 Center for Computational Sciences, Mississippi State University, Mississippi State, MS 39762, USA
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Chandran A, Kaszlikowski D, Sen De A, Sen U, Vedral V. Regional versus global entanglement in resonating-valence-bond states. PHYSICAL REVIEW LETTERS 2007; 99:170502. [PMID: 17995311 DOI: 10.1103/physrevlett.99.170502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 07/18/2007] [Indexed: 05/25/2023]
Abstract
We investigate the entanglement properties of resonating-valence-bond states on two and higher dimensional lattices, which play a significant role in our understanding of various many-body systems. We show that these states are genuinely multipartite entangled, while there is only a negligible amount of two-site entanglement. We comment on possible physical implications of our findings.
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Affiliation(s)
- Anushya Chandran
- Department of Electrical Engineering, The Indian Institute of Technology Madras, Chennai, India
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Powell BJ, McKenzie RH. Symmetry of the superconducting order parameter in frustrated systems determined by the spatial anisotropy of spin correlations. PHYSICAL REVIEW LETTERS 2007; 98:027005. [PMID: 17358640 DOI: 10.1103/physrevlett.98.027005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Indexed: 05/14/2023]
Abstract
We study the resonating valence bond theory of the Hubbard-Heisenberg model on the half-filled anisotropic triangular lattice. Varying the frustration changes the wave vector of maximum spin correlation in the Mott insulating phase. This, in turn, changes the symmetry of the superconducting state that occurs at the boundary of the Mott insulating phase. We propose that this physics is realized in several families of quasi-two-dimensional organic superconductors.
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Affiliation(s)
- B J Powell
- Department of Physics, University of Queensland, Brisbane, Queensland 4072, Australia
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Sahebsara P, Sénéchal D. Antiferromagnetism and superconductivity in layered organic conductors: Variational cluster approach. PHYSICAL REVIEW LETTERS 2006; 97:257004. [PMID: 17280384 DOI: 10.1103/physrevlett.97.257004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Indexed: 05/13/2023]
Abstract
The kappa-(ET)2X layered conductors (where ET stands for BEDT-TTF) are studied within the dimer model as a function of the diagonal hopping t' and Hubbard repulsion U. Antiferromagnetism and d-wave superconductivity are investigated at zero temperature using variational cluster perturbation theory (VCPT). For large U, Néel antiferromagnetism exists for t' < t(c2)', with t(c2)' approximately 0.9. For fixed t', as U is decreased (or pressure increased), a d(x2-y2) superconducting phase appears. When U is decreased further, then a d(xy) order takes over. There is a critical value of t(c1)' approximately 0.8 of t' beyond which the AF and dSC phases are separated by the Mott disordered phase.
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Affiliation(s)
- P Sahebsara
- Département de physique and Regroupement québécois sur les matériaux de pointe, Université de Sherbrooke, Sherbrooke, Québec, Canada, J1K 2R1
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Powell BJ. Mixed order parameters, accidental nodes and broken time reversal symmetry in organic superconductors: a group theoretical analysis. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2006; 18:L575-L584. [PMID: 21690918 DOI: 10.1088/0953-8984/18/46/l01] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We present a group theoretical analysis of several classes of organic superconductor. We predict that highly frustrated organic superconductors, such as κ-(ET)(2)Cu(2)(CN)(3) (where ET is BEDT-TTF, bis(ethylene-dithio)tetrathiafulvalene) and β'-[Pd(dmit)(2)](2)X, undergo two superconducting phase transitions, the first from the normal state to a d-wave superconductor and the second to a d+id state. We show that the monoclinic distortion of κ-(ET)(2)Cu(NCS)(2) means that the symmetry of its superconducting order parameter is different from that of orthorhombic κ-(ET)(2)Cu[N(CN)(2)]Br. We propose that β'' and θ phase organic superconductors have d(xy)+s order parameters.
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Affiliation(s)
- B J Powell
- Department of Physics, University of Queensland, Brisbane, Queensland 4072, Australia
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Kyung B, Tremblay AMS. Mott transition, antiferromagnetism, and d-wave superconductivity in two-dimensional organic conductors. PHYSICAL REVIEW LETTERS 2006; 97:046402. [PMID: 16907597 DOI: 10.1103/physrevlett.97.046402] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Indexed: 05/11/2023]
Abstract
We study the Mott transition, antiferromagnetism, and superconductivity in layered organic conductors using the cellular dynamical mean-field theory for the frustrated Hubbard model. A d-wave superconducting phase appears between an antiferromagnetic insulator and a metal for t'/t=0.3-0.7 or between a nonmagnetic Mott insulator (spin liquid) and a metal for t'/t>or=0.8, in agreement with experiments on layered organic conductors including kappa-(ET)2Cu2(CN)3. These phases are separated by a strong first-order transition. The phase diagram gives much insight into the mechanism for -wave superconductivity. Two predictions are made.
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Affiliation(s)
- B Kyung
- Département de Physique and Regroupement Québécois sur les Matériaux de Pointe, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
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Kato R, Tajima A, Nakao A, Tamura M. Two Pressure-Induced Superconducting Anion Radical Salts Exhibiting Different Spin States at Ambient Pressure. J Am Chem Soc 2006; 128:10016-7. [PMID: 16881622 DOI: 10.1021/ja063525l] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pressure-induced superconducting behavior was found in two anion radical salts, EtMe3Z[Pd(dmit)2]2 (dmit = 1,3-dithiole-2-thione-4,5-dithiolate, Z = P, As), that are Mott insulators and exhibit different magnetic and structural transitions at ambient pressure.
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Affiliation(s)
- Reizo Kato
- RIKEN, JST-CREST, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
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Liu J, Schmalian J, Trivedi N. Pairing and superconductivity driven by strong quasiparticle renormalization in two-dimensional organic charge transfer salts. PHYSICAL REVIEW LETTERS 2005; 94:127003. [PMID: 15903952 DOI: 10.1103/physrevlett.94.127003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Indexed: 05/02/2023]
Abstract
We introduce and analyze a variational wave function for quasi-two-dimensional kappa-(ET)(2) organic salts containing strong local and nonlocal correlation effects. We find an unconventional superconducting ground state for intermediate charge carrier interaction, sandwiched between a conventional metal at weak coupling and a spin liquid at larger coupling. Most remarkably, the excitation spectrum is dramatically renormalized and is found to be the driving force for the formation of the unusual superconducting state.
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Affiliation(s)
- Jun Liu
- Department of Physics and Astronomy and Ames Laboratory, Iowa State University, Ames, Iowa 50011, USA
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