Peierls Structural Transition in Q1D Organic Crystals of TTT<SUB>2</SUB>I<SUB>3</SUB>for Different Values of Carrier Concentration

• 作者: Anatolie Casian
• 来源期刊: 材料物理与化学进展(英文)
• 学科: 物理学
• 关键词: Quasi-One-Dimensional Organic Crystals Peierls Structural Transition TTT₂I₃ Renormalized Phonon Spectrum Interchain Interaction Peierls Critical Temperature
• 年，卷（期）: 2020,（10）
• 页码范围: 239-251
• 页数: 13页
• 分类号: O48

摘要

The Peierls structural transition in the TTT₂I₃ (tetrathiotetracene-iodide) crystal, for different values of carrier concentration is studied in 3D approximation. A crystal physical model is applied that considers two of the most important hole-phonon interactions. The first interaction describes the deformation potential and the second one is of polaron type. In the presented physical model, the interaction of carriers with the structural defects is taken into account. This is crucial for the explanation of the transition. The renormalized phonon spectrum is calculated in the random phase approximation for different temperatures applying the method of Green functions. The renormalized phonon frequencies for different temperatures are presented in two cases. In the first case the interaction between TTT chains is neglected. In the second one, this interaction is taken into account. Computer simulations for the 3D physical model of the TTT₂I₃ crystal are performed for different values of dimensionless Fermi momentum <em>k</em>_F, that is determined by variation of carrier concentration. It is shown that the transition is of Peierls type and strongly depends on iodine concentration. Finally, the Peierls critical temperature was determined.