У оквиру семинара Центра за изучавање комплексних система Института за физику у Београду, у четвртак, 6. новембра 2025. године у 14 часова у сали „Звонко Марић“ у оквиру пројекта Polaron Mobility in Model Systems and Real Materials (PolMoReMa), др Вељко Јанковић (Лабораторија за примену рачунара у науци, Институт за физику у Београду) одржаће предавање:
Quantum dynamics of charge transport in the field of slow off-diagonal dynamic disorder
САЖЕТАК:
The motion of a charge carrier in organic molecular crystals is mainly limited by its moderate coupling to slow and abundantly thermally excited intermolecular phonons [1]. Despite recent advances in fully
quantum methods, computations of transport properties most often rely on Newtonian [2] or some effective phonon dynamics [3]. This holds true even for the one-dimensional Peierls model featuring a single phonon mode per lattice site [4].
In this second SCL & PolMoReMa seminar, we present our numerically exact hierarchical equations of motion (HEOM)-based framework to compute transport properties of the one-dimensional Peierls model [5,6]. The phonon-assisted current is handled using our explicit expression of HEOM auxiliary operators in terms of phonon creation and annihilation operators [5]. We find that the displaced Drude peak [3] is accompanied by an optical-conductivity enhancement below phonon frequency [6], which is not observed in experimental low-frequency signatures. Solving the dissipaton equations of motion for a more realistic model with a continuous distribution of phonon modes, we conclude that this enhancement is an artifact of the assumed delta-like density of phonon states [7].
This research is supported by the Science Fund of the Republic of Serbia, Grant No. 5468, Polaron Mobility in Model Systems and Real Materials – PolMoReMa.
[1] B. M. T. C. Peluso et al., Angew. Chem. Int. Ed. 2025, e202507566 (2025).
[2] A. Troisi and G. Orlandi, Phys. Rev. Lett. 96, 086601 (2006).
[3] S. Fratini, D. Mayou, and S. Ciuchi, Adv. Funct. Mater. 26, 2292 (2016).
[4] J. E. Runeson, T. J. G. Drayton, and D. E. Manolopoulos, J. Chem. Phys. 161, 144102 (2024).
[5] V. Janković, Phys. Rev. B 112, 035111 (2025).
[6] V. Janković, Phys. Rev. B 112, 035112 (2025).
[7] V. Janković, arXiv:2508.14447 (2025).