Speaker
Description
Computation of lattice dynamics including anharmonic effects at a given temperature is critically important for describing phonon transport in extended solids, accurately. I will showcase with few examples, how temperature dependent effective potential (TDEP) method [1] in combination with ab-initio molecular dynamics (AIMD) simulations aid to describe the anharmonic lattice dynamics, consequently, accurate description of phonon transport in low lattice thermal conductivity (kl) materials. Designing materials with an ultralow kl is of paramount importance for thermal energy management applications. For instance, several strategies have been proposed to achieve ultralow kl, among them, the interplay of lone pair, layered structure, mass contrast between constituent elements in a material provide a pathway for engineering anharmonicity, bonding heterogeneity, flat and soft phonon bands to increase phonon-phonon scattering channels to suppress kl [2-4]. Layered materials consisting of a lone pair cation with mass contrast [4,5] aid to design ultralow kl materials. However, AIMD simulations are computationally very demanding, therefore, we adopt methodology training on-the-fly machine learning force fields (MLFFs) using AIMD simulations [6]. The MLFFs allow us to perform MD simulations for longer time and length scales within classical MD simulation time close to ab-initio accuracy. This would enable us to predict the properties of materials at finite temperatures, which remains as a longstanding problem in computational materials science.
- Hellman, O.; et al, Phys. Rev. B, 2011, 84, 180301.
- Larita, G.; Sheshadri, R.; Acc. Chem. Res., 2022, 55, 1004-1014.
- Yedukondalu, N.; et al, ACS Applied Mater. & Inter., 2022, 14, 40738-40748.
- Yedukondalu, N.; Pandey, T.; Rakesh Roshan, S. C., 2022, arxiv:2205.07091.
- Rakesh Roshan, S. C.; Yedukondalu, N.; et al, ACS Appl. Energy Mater., 2022, 5, 882-890.
- Liu, P. et al, Phys, Rev. B, 2022, 105, L060102.
