SCL Seminar by Ivana Savic

Scientific Computing Laboratory seminar will be held on Thursday 21 April 2016 at 14:00 in the library reading room "Dr Dragan Popovic" of the Institute of Physics Belgrade. The talk entitled

"Understanding and Manipulating Lattice Instability of PbTe for Improved Thermoelectric Performance"

will be given by Dr Ivana Savic (Tyndall National Institute, Cork, Ireland).

Abstract of the talk:

Thermoelectric materials could play an important role in energy harvesting and solid state cooling applications since they enable conversion between thermal and electrical energy [1]. The key physical properties for good thermoelectric performance are high electrical conductivity, high Seebeck coefficient and low thermal conductivity [1]. In many materials the improvement of one of these characteristics leads to a disimprovement of others, and the optimization of the overall thermoelectric performance is highly challenging.

It has been recently proposed that the proximity to a structural phase transition of PbTe is one of the key factors leading to its low thermal conductivity and high thermoelectric efficiency [2]. In this talk, using first principles calculations, I will show that driving PbTe closer to the structural phase transition via strain or alloying could substantially suppress its thermal conductivity [3]. Furthermore, using a combination of ultrafast X-ray scattering measurements and first principles calculations, I will show that the coupling of the electronic states near the band edges to transverse optical phonons drives PbTe near the structural instability [4]. These insights may open new opportunities for the development of more efficient thermoelectric materials.

[1] G. J. Snyder and E. S. Toberer, Nat. Mater. 7, 105 (2008).
[2] O. Delaire et al., Nat. Mater. 10, 614 (2011).
[3] R. M. Murphy, E. D. Murray, S. Fahy, and I. Savic, Phys. Rev. B 93, 104304 (2016)
[4] M. P. Jiang, M. Trigo, I. Savic et al., submitted.