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O: Fachverband Oberflächenphysik
O 70: Poster Session V: Poster to Mini-Symposium: Frontiers of electronic-structure theory II
O 70.5: Poster
Wednesday, March 3, 2021, 10:30–12:30, P
Uncovering the Relationship Between Thermal Conductivity and Anharmonicity with Symbolic Regression — •Thomas Purcell, Matthias Scheffler, Luca Ghiringhelli, and Christian Carbogno — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
Quantitatively understanding the link between anharmonicity and thermal conductivity, κ, is pivotal to the search for better thermal insulators. While it is qualitatively known that more anharmonic materials have a lower κ, until recently, no quantitative measure of anharmonicity existed. Here we present descriptors of κ based on our new measure of anharmonicity, σA [1]. We find the analytical expressions with symbolic regression, via the sure-independence screening and sparsifying operator (SISSO) method [2]. To better capture the nonlinearities in the correlation between κ and σA, we introduce an automatic scaling and shifting of the input data when generating new features like exp(α x + a). Using our new strategy, we generate expressions that are competitive with those previously reported in the literature using only a third of primary the features [3], and reduce the test error of the models when compared to traditional SISSO. Finally, we discuss the implications of the new models on future materials design.
[1] F. Knoop, et al. Phys. Rev. Mat. 4. 083809 (2020)
[2] R. Ouyang, et al. Phys. Rev. Mat. 2. 083802 (2018)
[3] L. Chen, et al., J. Com. Mat. Si. 170. 109155 (2019)