Oral: Computational studies of magnetism and topological phases in SmAgSb₂

SmAgSb₂ is a member of the family of materials that possesses topological fermions due to the square net of Sb ions contained in its structure. Previous studies suggest that a topological phase transition exists in conjunction with an antiferromagnetic ordering transition at low temperature. In this project, density functional theory calculations were used to supplement experimental measurements. Magnetic susceptibility and heat capacity data hint at a rich magnetic behavior at higher temperatures beyond Curie-Weiss paramagnetism and high magnetoresistance observed may indicate contributions form berry curvature. Ab initio calculations have been used to confirm the fermi surface with temperature as shown experimentally through quantum oscillations and ARPES data, as well as predicting the magnetic structure of SmAgSb₂ at low temperatures. Initial comparisons between possible magnetic structures at low temperatures were done by considering the magnetic 4f electrons of Samarium, pointing to an interlayer antiferromagnetic ordering along the c direction. More rigorous calculations were done to verify this structure by also including contributions from the Hubbard model, which is a simplistic way of considering electron correlation effects not considered by traditional DFT.