Role of layer packing for the electronic properties of the organic superconductor (BEDT-TTF)${}_2$Ag(CF${}_3$)${}_4$(TCE)

Abstract

The charge transfer compound (BEDT-TTF)${}_2$Ag(CF${}_3$)${}_4$(TCE) crystallizes in three polymorphs with different alternating layers: While a phase with a $\kappa$ packing motif has a low superconducting transition temperature of $T_c=2.6$ K, two phases with higher $T_c$ of $9.5$ and $11$ K are multi-layered structures consisting of ${\alpha }^{\prime }$ and $\kappa$ layers. We investigate these three systems within density functional theory and find that the ${\alpha }^{\prime }$ layer shows different degrees of charge order for the two $\kappa$-${\alpha }^{\prime }$ systems and directly influences the electronic behavior of the conducting $\kappa$ layer. We discuss the origin of the distinct behavior of the three polymorphs and propose a minimal tight-binding Hamiltonian for the description of these systems based on projective molecular Wannier functions.

arXiv comment8 pages, 12 figures

References in corpus (6)

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• Ab initio Derivation of Low-Energy Model for $\kappa$-ET Type Organic Conductors
• Strong electronic correlations in superconducting organic charge transfer salts
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• Evidence for eight node mixed-symmetry superconductivity in a correlated organic metal
• Influence of molecular conformations on the electronic structure of organic charge transfer salts
• Ab initio determination of spin Hamiltonians with anisotropic exchange interactions: the case of the pyrochlore ferromagnet Lu${}_2$V${}_2$O${}_7$