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

We present recent advances in our Locally-selfconsistent Multiple Scattering (LSMS) code for scalable first principles density functional calculations of materials. A fundamental science drivers for large scale calculations is the need to understand materials beyond periodic crystalline lattices. Due to the large simulation cells of many thousands of atoms needed to describe complex electronic and magnetic ordering, defect states or disorder in alloys, the cubic scaling of traditional first principles methods has prevented direct first principles calculations. The real space formalism of LSMS enables calculations for O(100,000) atom. In preparation for exascale systems, we are extending the use of accelerators to the calculation of forces and embedding methods for disordered systems. We will 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]