Berlin 2024 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 13: Poster I

HL 13.23: Poster

Montag, 18. März 2024, 15:00–18:00, Poster E

Study of the metal-insulator transition of Peierls type in quasi-one-dimensional organic crystals. — •Silvia Andronic and Ionel Sanduleac — Technical University of Moldova, Stefan cel Mare ave. 168, MD-2004, Chisinau, Republic of Moldova

The purpose of the current study is to investigate the metal-insulator transition occurring in quasi-one-dimensional organic crystals (Q1D) of TTF-TCNQ, TTT(TCNQ)2 and TTT2I3. The use of these materials brings several advantages, including cost-effectiveness, environmental safety and relatively inexpensive manufacturing processes. Additionally, the growing interest in certain Q1D organic crystals is attributed to their high electrical conductivity. The research employs a 3D approximation method and introduces a physical model that incorporates two significant electron-phonon interaction mechanisms, one akin to the deformation potential and the other exhibiting polaron characteristics. We also account for scattering on defects, a crucial factor in explaining the transition. Using the random phase approximation and Green functions method, we calculate the phonon polarization operator and the renormalized phonon spectrum at different temperatures and various dimensionless Fermi momentum (kF) values. The results suggest that the transition demonstrates Peierls-type characteristics, and the critical temperature linked to the Peierls transition is identified. Furthermore, we observed that the Peierls critical temperature significantly decreases as the carrier concentration increases. The impact of lattice distortion on the dispersion of renormalized acoustic phonons is also considered.

Keywords: Metal-insulator transition; Organic materials; Quasi-one-dimensional organic crystals; Renormalized phonon spectrum; Peierls critical temperature