ANALYSIS OF PHONONS BEHAVIOR IN QUASI-ONE-DIMENSIONAL CRYSTALS OF TTT(TCNQ)2 NEAR THE PEIERLS STRUCTURAL TRANSITION IN A 3D APPROXIMATION

This research paper focuses on investigating the metal-insulator transition occurring in quasi-one-dimensional organic crystals of TTT(TCNQ)2. The study utilizes a 3D approximation approach and introduces a physical model that incorporates two essential electron-phonon interactions. The first interaction is akin to the deformation potential, while the second interaction follows a polaron type behavior. By employing the random phase approximation, the renormalized phonon spectrum is calculated across different temperatures and various values of the dimensionless Fermi momentum kF. The findings indicate that the transition exhibits characteristics of the Peierls type, and the critical temperature associated with the Peierls transition is determined. Furthermore, an interesting observation is made that the Peierls critical temperature experiences a notable decrease with an increase in carrier concentration.