Wednesday Colloquia

Crystalline Solids with Intrinsically Low Lattice Thermal Conductivity for Thermoelectric Energy Conversion

by Prof. Kanishka Biswas (JNCASR Bangalore)

Wednesday, September 30, 2020 from to (Asia/Kolkata)
at Online through ZOOM Webinar ( Zoom link: )
Meeting ID: 979 6325 9354 Pass code: 04072020
One of the fundamental challenges in developing high-performance thermoelectric materials has been to achieve low lattice thermal conductivity (κL) in crystalline inorganic solids. The exploration of new materials with intrinsically low κL along with understanding of the correlations among chemical bonding, lattice dynamics and phonon transport are fundamentally important towards designing high performance thermoelectric materials. I will demonstrate how a weakly bonded cation in a cage like structure of a Zintl compound creates dynamical rattling instability, thus creating significant lattice anharmonicity and fosters ultralow κL in TlSe.[1] Finally, I will show how the local structural distortions and the associated ferroelectric lattice instability induced soft polar optical phonons effectively scatter the heat carrying acoustic phonons and help achieve ultralow κL in SnTe and GeSe.[2] 

[1] M. Dutta, S. Matteppanavar, M. V. D. Prasad, J. Pandey, A. Warankar, P.   Mandal, A. Soni, U. V. Waghmare, K. Biswas, J. Am. Chem. Soc. 2019, 141, 20293.  

[2] D. Sarkar, T. Ghosh, S. Roychowdhury, R. Arora, S. Sajan, G. Sheet, U. V. Waghmare, K. Biswas, J. Am. Chem. Soc. 2020, 142, 12237.