[institut] Reminder - SCL & PolMoReMa Seminar: Suzana Miladić, Thursday 27 November, 14:00

[Nenad Vukmirović]

Dear colleagues,

This is a reminder about the seminar taking place today.

Best regards,
Nenad Vukmirović

-- 
Dr Nenad Vukmirović
Research Professor
Scientific Computing Laboratory
Center for the Study of Complex Systems
Institute of Physics Belgrade
Pregrevica 118, 11080 Belgrade, Serbia
URL: http://www.scl.rs/nenad


On 21. 11. 25. 09:05, Nenad Vukmirović wrote:
> Dear colleagues,
>
> You are cordially invited to the seminar of the Scientific Computing 
> Laboratory of the Center for the Study of Complex Systems and of the 
> project Polaron Mobility in Model Systems and Real Materials 
> (PolMoReMa). The seminar will be held on Thursday, 27 November 2025 at 
> 14:00 in the library reading room "Dr Dragan Popović" of the Institute 
> of Physics Belgrade. The talk entitled
>
> QMC study of transport in Holstein polaron model
>
> will be given by Suzana Miladić (Scientific Computing Laboratory, 
> Institute of Physics Belgrade). The abstract of the talk:
>
> Organic semiconductors are emerging materials that are shaping modern 
> technologies (OLEDs, OFETs, OPVs). Their low cost, mechanical 
> flexibility, and tunable properties make them highly promising for a 
> wide range of applications. However, realizing their full potential 
> requires a detailed understanding of charge transport in these materials.
>
> In this work, we investigate transport within the Holstein polaron 
> model—a simple yet representative framework for organic molecular 
> semiconductors. We develop a path-integral Quantum Monte Carlo method 
> for computing current–current correlation functions and the dc 
> mobility in the 1D Holstein model [1]. By carefully choosing the basis 
> for the trace expansion in path integral, we suppress the dynamical 
> sign problem and are able to evaluate correlation functions over long 
> real-time intervals with small errors.
>
> Using the Kubo formula, we extract the dc mobility either through 
> direct integration of real-time correlation functions or via analytic 
> continuation that combines real- and imaginary-time data. This 
> approach yields highly precise results for dc mobility across a broad 
> parameter range. The numerically exact results obtained here provide a 
> great benchmark for evaluating the validity of commonly used transport 
> theories, which rely on approximations appropriate only in extreme 
> cases (strong or weak electron–phonon coupling, very low or high 
> temperature).
>
> By comparing our numerical results to the predictions of each 
> transport theory, we are able to map out the parameter ranges—defined 
> by temperature, electron–phonon interaction strength, and phonon 
> frequency—over which small-polaron hopping, polaron band transport, or 
> conventional band transport offers an accurate description of charge 
> transport. This allows us to construct a transport-regime diagram for 
> the 1D Holstein model, offering better insights into its transport 
> behavior [2].
>
> 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] S. Miladić and N. Vukmirović, Phys. Rev. B 107, 184315 (2023).
> [2] S. Miladić and N. Vukmirović, Phys. Rev. B 112, 054314 (2025).
>
> Best regards,
> Nenad Vukmirović
>