Mechanism of superconductivity and electron-hole doping asymmetry in $\kappa$-type molecular conductors

Abstract

Unconventional superconductivity in molecular conductors is observed at the border of metal-insulator transitions in correlated electrons under the influence of geometrical frustration. The symmetry as well as the mechanism of the superconductivity (SC) is highly controversial. To address this issue, we theoretically explore the electronic properties of carrier-doped molecular Mott system $\kappa$-(BEDT-TTF)${}_2$X. We find significant electron-hole doping asymmetry in the phase diagram where antiferromagnetic (AF) spin order, different patterns of charge order, and SC compete with each other. Hole-doping stabilizes AF phase and promotes SC with "$d_{xy}$"-wave symmetry, which has similarities with high-$T_c$ cuprates. In contrast, in the electron-doped side, geometrical frustration destabilizes the AF phase and the enhanced charge correlation induces another SC with "extended-$s$+$d_{x^2-y^2}$"-wave symmetry. Our results disclose the mechanism of each phase appearing in filling-control molecular Mott systems, and elucidate how physics of different strongly-correlated electrons are connected, namely, molecular conductors and high-$T_c$ cuprates.

10 pages, 5 figures, to be published in Nat. Commun

References in corpus (16)

• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Mott Transition from a Spin Liquid to a Fermi Liquid in the Spin-Frustrated Organic Conductor kappa-(ET)2Cu2(CN)3
• Unconventional critical behaviour in a quasi-two-dimensional organic conductor
• Mott Transition, Antiferromagnetism, and d-wave Superconductivity in Two-Dimensional Organic Conductors
• Nodal Structure of Unconventional Superconductors Probed by the Angle Resolved Thermal Transport Measurements
• Specific heat measurements of the gap structure of the organic superconductors kappa-(ET)_2Cu[N(CN)_2]Br and kappa-(ET)_2Cu(NCS)_2
• Exact diagonalization study of Mott transition in the Hubbard model on an anisotropic triangular lattice
• Symmetry of the superconducting order parameter in frustrated systems determined by the spatial anisotropy of spin correlations
• Electron-hole doping asymmetry of Fermi surface reconstructed in a simple Mott insulator
• Phase Competition and Superconductivity in $\kappa$-(BEDT-TTF)${}_2$X: Importance of Intermolecular Coulomb Interactions
• Non-linear charge oscillation driven by a single-cycle light-field in an organic superconductor
• Superconductivity in correlated BEDT-TTF molecular conductors: critical temperatures and gap symmetries
• Critical Behavior in Doping-Driven Metal$-$Insulator Transition on Single-Crystalline Organic Mott-FET
• Polar Charge Fluctuation and Superconductivity in Organic Conductor
• Dynamical reduction of the dimensionality of exchange interactions and the "spin-liquid" phase of $\kappa$-(BEDT-TTF)${}_{2}X$
• Charge orders in organic charge-transfer salts

Cited by in corpus (11)

• Spin current generation in organic antiferromagnets
• Anomalous Hall effect in $\kappa$-type organic antiferromagnets
• Fulde-Ferrell-Larkin-Ovchinnikov state induced by antiferromagnetic order in $\kappa$-type organic conductors
• Symmetry change of $d$-wave superconductivity in $\kappa$-type organic superconductors
• Antiferromagnetic State in $\kappa$-type Molecular Conductors: Spin Splitting and Mott Gap
• Simultaneous Control of Bandfilling and Bandwidth in Electric Double-Layer Transistor Based on Organic Mott Insulator $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Cl
• Thermodynamic Properties of the Mott Insulator-Metal Transition in a Triangular Lattice System Without Magnetic Order
• Prediction of pseudogap formation due to $d$-wave bond-order in organic superconductor $\kappa$-(BEDT-TTF)${}_2$X
• Theory of triangular lattice quasi-one-dimensional charge-transfer solids
• Density Matrix Renormalization Group study of superconducting pairing near the quarter-filled Wigner crystal
• Possibility of BCS-BEC crossover in $\kappa$-type organic superconductors