Evaluating model parameters of the κ - and β ′ -type Mott insulating organic solids

Takashi Koretsune, Chisa Hotta

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)

Abstract

We elucidate the model parameters for a series of organic crystals called κ- and β′-type salts by constructing the maximally localized Wannier orbitals which reproduce the bulk energy band of the first-principles methods based on the density functional theory (DFT). These materials host a dimer Mott insulator, localizing one hole per dimerized ET molecules due to strong on-dimer interaction, Ud. For all these materials, we evaluate the parameters of the two representative effective lattice models in units of molecule and on dimer, and clarify two issues. First, the conventional relationships between the two models called "dimer approximation" does not hold. Second, contrary to the previous semiempirical estimates, the degree of dimerization (which approximates Ud) does not depend much on materials, and that the overall ground state properties are controlled by the degree of anisotropy of the triangular lattice, denoted as |tc/ta| in units of dimers. We update the DFT estimates |tc/ta| of κ-ET2Cu2(CN)3, showing that it falls on a class of regular triangle with the strongest degree of frustration.

Original languageEnglish
Article number045102
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume89
Issue number4
DOIs
Publication statusPublished - 2014 Jan 3
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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