2022 Workshop on Recent Developments in Electronic Structure (ES22) Poster Session

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Author: Eskridge, Brandon - College of William and Mary

Title: Ab Initio Treatment of Molecular Magnets using Auxiliary-field quantum Monte Carlo (AFQMC)

Abstract: Molecular magnets have seen significant attention due to their potential applications in quantum information / quantum computing. A delicate balance of electron correlation, spin-orbit coupling (SOC), ligand field splitting, and other effects produces a persistent magnetic moment within each molecular magnet unit. The competition among these effects poses a challenge for theoretical treatments. Electron correlation effects play a central role since d-, or f-element ions provide the magnetic states in molecular magnets requiring explicit many-body treatments in general. In addition, the explicit inclusion of SOC expands the dimensionality of the Hilbert space that must be treated. Furthermore, molecular magnets are large systems involving tens of atoms in even the smallest systems. Auxiliary-field quantum Monte Carlo (AFQMC) has demonstrated a high degree of reliability in correlated-electron systems with computational cost that scales as a low order polynomial making applications to large systems feasible. Recent advances in AFQMC technology allow an ab initio treatment in molecular magnets where electron correlation, SOC, and material specificity are included accurately and on an equal footing. We demonstrate the approach by applying AFQMC to compute the zero-field splitting (ZFS) of a linear Co(II) complex.

Other authors: Krakauer, Henry - College of William and Mary;  Zhang, Shiwei - Flatiron Institute Center for Computational Quantum Physics