Peierls structural transition in organic crystals of TTT2I3 : 2D modeling

Abstract

The Peierls structural transition in quasi-one-dimensional organic crystals of tetrathiotetracene iodide (TTT2I3) with a quarter filled zone is studied in 2D physical model. A more complete crystal model is used which takes into account two main hole-phonon interactions. One of them is of deformation potential type and the other is similar to that of polaron. The ratios of amplitudes of the second interaction to the first one along the chains and in transversal directions are characterized by the parameters γ1 and γ2, respectively. The polarization operator as a function of temperature is calculated for different values of the parameter d, where d is the ratio of the transfer energy in the direction transversal to conductive hains to the transfer energy along the conductive chains. The Peierls critical temperature Tp was determined for Fermi dimensionless quasi momentum kF = /4 and for different values of γ1.