Computational Materials Discovery by RESCU - a KS-DFT method for solving thousands of atoms

A major bottleneck for solving realistic materials problems is the lack of a first principles method that can accurately, efficiently and comfortably calculate condensed phase materials comprising thousands of atoms. Solving large systems is necessary when dealing with structures involving interfaces, surfaces, dilute impurities, grain boundaries, dislocations, domains, solvents etc. Well-known methods of Kohn–Sham density functional theory (KS-DFT) can solve problems at a few hundred atoms level on a modest computer. For larger systems, supercomputers or further approximations are necessary. Here I shall present our effort in developing a general-purpose KS-DFT solver called RESCU (stand for real space electronic structure calculator). We demonstrate that RESCU can easily compute electronic structure for systems comprising thousands of atoms on a modest computer, for metals, semiconductors, insulators, liquids, moire patterns in 2D heterjunction materials, dilute doped III-nitrides etc. For these problems and up to 14,000 atoms as we have used it for, RESCU converges KS-DFT in a few to ten wall-clock hours. RESCU achieves high efficiency without compromising accuracy. I shall present the novel computational mathematics behind the efficiency gain¹, and apply it for property discovery of materials.

Acknowledgements: I wish to thank Dr. Lei Zhang who participated earlier work in this effort, and Dr. Xiaobin Chen for the phonon package. Many other researchers generously helped us to improve and apply RESCU, and they will be acknowledged during the presentation. Funding from NSERC of Canada is gratefully acknowledged.