Semi-Automated Creation of Density Functional Tight Binding Models through Leveraging Chebyshev Polynomial-Based Force Fields

• Published in: Journal of chemical theory and computation Vol. 17; no. 7; pp. 4435 - 4448
• Main Authors: Goldman, Nir, Kweon, Kyoung E, Sadigh, Babak, Heo, Tae Wook, Lindsey, Rebecca K, Pham, C. Huy, Fried, Laurence E, Aradi, Bálint, Holliday, Kiel, Jeffries, Jason R, Wood, Brandon C
• Format: Journal Article
• Language: English
• Published: Washington American Chemical Society 13-07-2021
• Subjects: Binding; Chebyshev approximation; Chemical calculations; Chemical properties; Condensed matter physics; Condensed Matter, Interfaces, and Materials; Density functional theory; Electron states; Energy; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Kinetic parameters; Many body interactions; Molecular dynamics; Polynomials; Surface energy; Surface properties; Unit cell; Workflow
• ISSN: 1549-9618; 1549-9626
• DOI: 10.1021/acs.jctc.1c00172

Density functional tight binding (DFTB) is an attractive method for accelerated quantum simulations of condensed matter due to its enhanced computational efficiency over standard density functional theory (DFT) approaches. However, DFTB models can be challenging to determine for individual systems of interest, especially for metallic and interfacial systems where different bonding arrangements can lead to significant changes in electronic states. In this regard, we have created a rapid-screening approach for determining systematically improvable DFTB interaction potentials that can yield transferable models for a variety of conditions. Our method leverages a recent reactive molecular dynamics force field where many-body interactions are represented by linear combinations of Chebyshev polynomials. This allows for the efficient creation of multi-center representations with relative ease, requiring only a small investment in initial DFT calculations. We have focused our workflow on TiH2 as a model system and show that a relatively small training set based on unit-cell-sized calculations yields a model accurate for both bulk and surface properties. Our approach is easy to implement and can yield reliable DFTB models over a broad range of thermodynamic conditions, where physical and chemical properties can be difficult to interrogate directly and there is historically a significant reliance on theoretical approaches for interpretation and validation of experimental results.