Peierls structural phase transition in quasi-one-dimensional organic crystals

Abstract

The aim of this paper is to study the Peierls transition in Q1D organic crystals of TTF-TCNQ (tetrathiofulvalinium-tetracyanoquinodimethane) and TTT2I3 (tetrathiotetracene iodide). The first crystal has the conduction band filled at half, but the second has a band filled by one quarter. Unlike the previous papers, we apply for Q1D organic crystals a more compel physical model than so far. Two electron-phonon interactions are considered. The first is similar to that of deformation potential and is connected with the fluctuations due to lattice vibrations of the transfer energy of an electron from one molecule to the nearest one along the molecular chains.