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Correlation-driven modifications to the low energy electronic states in iron-based superconductors
Speaker: Ming Yi (Rice University)
Electronic correlation is of fundamental importance to high temperature superconductivity. Iron-based superconductors are believed to possess moderate correlation strength, which combined with their multi-orbital nature makes them a fascinating platform for the emergence of exotic phenomena. A particularly striking form is the emergence of an orbital selective Mott phase, where the localization of a subset of orbitals leads to a drastically reconstructed Fermi surface. Here, I will present spectroscopic evidence of the reorganization of the low energy electronic states in iron chalcogenide materials as affected by both non-thermal isovalent substitution as well as temperature. We uncover a particularly transparent way to visualize the localization of the dxy electron orbital through the suppression of its hybridization with the more coherent d electron orbitals, leading to a redistribution of the orbital-dependent spectral weight near the Fermi level. These observations spell out the important roles played by both Coulomb interactions and Hund’s coupling in dictating the low energy properties in these fascinating materials.
Host: Gabi Kotliar