Required nearest-neighbor Coulomb interactions for a charge-ordered phase transition in (TMTTF)2MF6 with inversion symmetry breaking in crystal

Abstract

We examined the charge-ordered phase transition in (TMTTF)2MF6 systems by exact diagonalization of an extended Hubbard model Hamiltonian whose parameters were referred from quantum chemical calculations with periodic boundary conditions along with inversion symmetry breaking in the crystal. We showed that a nearest-neighbor Coulomb interactions for the charge-ordered phase transition should be twice as much as those previously obtained by fitting for conductivities with a minute inversion symmetry breaking of the crystal (∼0.01 Å) which was confirmed by a recent experimental study.