From LSMS to MuST: Large scale first principles materials calculations at the exascale

We present recent development of our Locally-selfconsistent Multiple Scattering (LSMS) code for scalable large scale first principles density functional calculations of materials. A fundamental science driver for scalable, large scale, first principles calculations of materials is the need to understand states beyond periodic crystalline lattices. For large simulation cells, needed to describe extended electronic and magnetic orderings, defect states or disorder in alloys, the cubic scaling of traditional first principles methods has prevented direct calculations. The real space formalism of LSMS enables calculations for O(10,000 - 100,000) atoms on Summit. In preparation for exascale systems, we are extending the use of accelerators to enable the efficient calculation for embedding methods and forces. We present results and performance measurements for defects in high entropy alloys and non-collinear magnetism in disordered systems. The computational capabilities will be available in our Multiple Scattering Theory suite (MuST) [https://github.com/mstsuite]