You are cordially invited to the SCL seminar of the Center for the Study of Complex Systems, which will be held on Wednesday, 13 June 2018 at 14:00 in the library reading room “Dr Dragan Popović” of the Institute of Physics Belgrade. The talk entitled
Electronic and Thermoelectric Transport in PbTe: Insights from First Principles Calculations
will be given by Dr Ivana Savić (Tyndall National Institute, Cork, Ireland).
Abstract of the talk:
Thermoelectric materials could play an important role in the development of energy harvesting technologies due to their ability to convert waste heat into electricity [1]. It is challenging to control and enhance the efficiency of thermoelectric energy conversion in a material because of the conflicting requirements for the desired physical properties i.e. high electrical conductivity and low thermal conductivity. Exploiting the fascinating properties of materials near soft mode phase transitions is an emerging concept in the quest to increase thermoelectric efficiency [2,3]. The underlying idea is that soft phonon modes lead to intrinsically low thermal conductivity, while possibly preserving high electronic conductivity. In this talk I will focus on the unusual electronic transport properties of n-type PbTe, which is a classic thermoelectric material that exists near a soft optical mode phase transition. Our first principles calculations show that most scattering mechanisms in PbTe are very weak, with the exception of that due to polar optical phonons [4,5]. Our results suggest that good thermoelectric materials may be found among weakly polar materials with symmetry forbidden scattering mechanisms.
[1] G. J. Snyder and E. S. Toberer, Nat. Mater. 7, 105 (2008).
[2] L.-D. Zhao et al, Nature 508, 373 (2014).
[3] R. M. Murphy, E. D. Murray, S. Fahy, and I. Savic, Phys. Rev. B 93, 104304 (2016); Phys. Rev. B 95, 144302 (2017).
[4] A. R. Murphy, F. Murphy-Armando, S. Fahy, and I. Savic, submitted.
[5] J. Cao, J. D. Querales-Flores, A. R. Murphy, S. Fahy, and I. Savic, in preparation.