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Welcome to the MuST wiki! MuST, a Multiple Scattering Theory based the first principle public computational framework with exascale computing capability for the study of quantum phenomena in disordered materials.
MuST is developed based on full-potential multiple scattering theory, also known as the Korringa-Kohn-Rostoker (KKR) method, with Green's function approach. It is built upon decades of development of research codes led by Malcolm Stocks, and his postdocs and students, in the Theory Group of Metals and Ceramics Division, which later became the Materials Science and Technology Division, in Oak Ridge National Laboratory. The original research codes include Korringa-Kohn-Rostoker Coherent Potential Approximation (KKR-CPA), a highly efficient ab initio method for the study of random alloys, and Locally Self-consistent Multiple Scattering (LSMS) the method, a linear scaling ab initio code capable of treating extremely large disordered systems from the first principles using the largest parallel supercomputers available.
Ther starting point of the MuST package is the integration of two research codes: LSMS (formerly LSMS-3) and MST (formerly MST-2), both are originally based on the legacy LSMS-1 code developed in the mid of 1990s in Oak Ridge National Laboratory.
The LSMS code, maintained by Markus Eisenbach, is mainly written in C++. It consists of muffin-tin LSMS with an interface for Monte-Carlo simulation driver. The LSMS code is one of the baseline benchmark codes for DoE COREL systems and has also been selected as one of the CAAR projects for exascale computing on Frontier system. The LSMS code demonstrates nearly ideal linear scaling with 96% parallel scaling efficiency across the Titan machine at ORNL.
The MST code, maintained by Yang Wang, is mainly written in FORTRAN 90. It focuses on physics capabilities, and in the meantime serves as a platform for implementing and testing full- potential multiple scattering theory and its numerical algorithms. It consists of LSMS, KKR, and KKR-CPA codes and is capable of performing 1) muffin-tin and full-potential; 2) non-relativistic, scalar-relativistic, and fully-relativistic; and 3) non-spin-polarized, spin-polarized, and spin-canted ab initio electronic structure calculations.
As shown by model calculation, the strong disorder and localization effects can also be studied within the LSMS formalism with cluster embedding in an effective medium with the Typical Medium Dynamical Cluster Approximation (TMDCA), which enables a scalable approach for first principles studies of quantum materials.