Towards Large-scale Quantum Accuracy Materials Simulations*

Electronic structure calculations, especially those using density functional theory (DFT), have been very useful in understanding and predicting a wide range of materials properties. Despite the wide adoption of DFT, and the tremendous progress in theory and numerical methods over the decades, the following challenges remain. Firstly, many widely used implementations of DFT suffer from domain-size and geometry restrictions, limiting the complexity of materials systems that can be treated using DFT calculations. Secondly, there are many materials systems (such as strongly-correlated systems) where the widely used model exchange-correlation functionals in DFT, which account for the many-body quantum mechanical interactions between electrons, are not sufficiently accurate. 

 

This talk will discuss the recent advances towards addressing the aforementioned challenges. In particular, the development of computational methods and numerical algorithms for conducting fast and accurate large-scale DFT calculations using adaptive finite-element discretization will be presented, which form the basis for the recently released DFT-FE open-source code [1,2]. The computational efficiency, scalability and performance of DFT-FE will be presented, which demonstrates a significant outperformance of widely used plane-wave DFT codes. Some recent application studies that highlight the capabilities of DFT-FE will be presented. In addressing the second challenge, our recent progress in accurately solving the inverse DFT problem will be presented, which has enabled the computation of exact exchange-correlation potentials for polyatomic systems [3,4,5]. Ongoing efforts on using the exact exchange-correlation potentials to improve the exchange-correlation functional description in DFT will be discussed. 

 

[1] P. Motamarri et al., Comput. Phys. Commun. 246, 106853 (2020).

[2] S. Das et al., Comput. Phys. Commun. 280, 108473 (2022).

[3] B. Kanungo, P. Zimmerman, V. Gavini, Nature Communications 10, 4497 (2019).

[4] B. Kanungo, P. Zimmerman, V. Gavini, J. Phys. Chem. Lett. 12, 12012-12019 (2021).

[5] B. Kanungo, J. Hatch P. Zimmerman, V. Gavini, Exact and model exchange-correlation potentials for open shell systems, to appear in J. Phys. Chem. Lett. (2023); arXiv:2305.15620.