Phase competition and superconductivity in κ-(BEDT-TTF)2X: Importance of intermolecular Coulomb interactions

Hiroshi Watanabe, Hitoshi Seo, Seiji Yunoki

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Abstract

We theoretically study the competition among different electronic phases in molecular conductors κ-(BEDT-TTF)2X. The ground-state properties of a 3/4-filled extended Hubbard model with the κ-type geometry are investigated by a variational Monte Carlo method. We find various competing phases: dimer-Mott insulator, polar charge-ordered insulator, 3-fold charge-ordered metal, and superconductivity, whose pairing symmetry is an "extended-s + dx2 - y2"- wave type. Our results show that the superconducting phase is stabilized not on the verge of the Mott metal-insulator transition but near charge order instabilities, clearly indicating the importance of the intradimer charge degree of freedom and the intermolecular Coulomb interactions, beyond the simple description of the half-filled Hubbard model.

Original languageEnglish
Article number033703
JournalJournal of the Physical Society of Japan
Volume86
Issue number3
DOIs
Publication statusPublished - 2017

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

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