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, 16 October 2025 at 14:00 in the "Dragan Popović" lecture hall of the Institute of Physics Belgrade. The talk entitled

Grid-Free Evaluation of Phonon-Limited Electronic Relaxation Times and Transport Properties

will be given by Dr Nenad Vukmirović (Scientific Computing Laboratory, Institute of Physics Belgrade). The abstract of the talk:

This seminar is the first in the series of seminars by the members of the project PolMoReMa [1]. The goals and activities of the project will be briefly presented in the first part of the seminar. In the second part of the seminar, we will present our results on the development of methodology for efficient evaluation of phonon-limited electronic relaxation times and electrical transport properties in semiconducting materials. Namely, present calculations of electrical transport properties of materials require evaluations of electron-phonon coupling constants on dense predefined grids of electron and phonon momenta and performing the sums over these momenta [2, 3]. In this seminar, we present the methodology for calculation of carrier relaxation times and electrical transport properties without the use of a predefined grid [4]. The relaxation times are evaluated by integrating out the delta function that ensures energy conservation and performing an average over the angular components of phonon momentum. The charge carrier mobility is then evaluated as a sum over appropriately sampled electronic momenta. We illustrate our methodology by applying to the Fröhlich model and to a real semiconducting material ZnTe. We find that rather accurate results can be obtained with a modest number of electron and phonon momenta, on the order of one hundred each, regardless of the carrier effective mass.

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] http://polmorema.ipb.ac.rs
[2] S. Poncé, W. Li, S. Reichardt and F. Giustino, Rep. Prog. Phys. 83, 036501 (2020).
[3] N. Vukmirović, Phys. Rev. B 104, 085203 (2021).
[4] N. Vukmirović, Comput. Phys. Commun. 312, 109583 (2025).