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Event Date and Time
Brown Lab 219
Hao Shi, Flat Iron Institute
The emergent and fascinating phenomena in strongly correlated quantum materials are in the interests of both fundamental science, material design, and technological applications. A major challenge is to be able to accurately compute the properties of electrons in these materials. Auxiliary field quantum Monte Carlo is a promising numerical method for strongly correlated quantum systems. It is proven to be highly accurate and be able to treat large number of electrons in the Simons many-electron collaboration. We apply the state-of-art auxiliary field quantum Monte Carlo for realistic transition metal systems. The many-body ab initio Hamiltonian is treated directly on transition metal atoms, their ions, and their monoxide molecules. We show ionization energy and dissociation energy on transition metal systems are indistinguishable from experimental results. Then, we study the low temperature phase diagram of Ca2RuO4 for a range of layered perovskite structures. Our calculations find that the metal-insulator transition in Ca2RuO4 is driven by a structural transition and explain the origin of the magnetic and metal-insulator transitions in Ca2RuO4. Our many-body numerical method can be useful for a wide range of nanoscale problems in condensed matter physics, chemistry, and materials.