Kohn-Sham accuracy at a fraction of the cost: Nonlocal subsystem DFT and orbital-free DFT

Subsystem DFT enables first principles simulations to approach realistic time- and length-scales, and most importantly sheds light on the dynamical behavior of complex systems. The accuracy of subsystem DFT is dependent on the quality of the employed nonadditive Kinetic Energy Density Functionals (KEDF). As these are customarily of semilocal character (i.e., they depend locally on the value of the density and its gradient), so far subsystem DFT has only been able to approach weakly interacting subsystems. In this presentation, we employ latest-generation nonlocal KEDF^1,2 in subsystem DFT³ and orbital-free DFT⁴ simulations. Our results are of KS-DFT accuracy while still keeping the computational cost at a fraction of typical KS-DFT algorithms. The developed KEDFs are accurate enough also in the context of orbital-free DFT where we show they are able to approach million-atom semiconductor systems arranged in complex structures featuring Schottky barriers and space-charge regions.

1. W. Mi and M. Pavanello, Phys. Rev. B, 100, 041105 (2019)
2. W. Mi, A. Genova, and M. Pavanello, J. Chem. Phys., 148, 184107 (2018)
3. W. Mi and M. Pavanello, submitted.
4. X. Shao, W. Mi and M. Pavanello, in preparation.