Speaker
Description
Interaction effects in strongly correlated electron materials stabilize emergent electronic phases that promise the next technological revolution, such as superconductivity, Mott insulating states and density wave orders. To gain insight into the origin of these states and learn how to manipulate them, a deep understanding of their electronic structure and coupling to lattice and spin degrees of freedom is needed. However, the presence of the same interactions that lead to this rich physics hinders a simple identification of the underlying band structure, as they lead to broadening and additional features in spectroscopic techniques such as angle resolved photoemission spectroscopy (ARPES) and scanning tunnelling microscopy (STM).
Electronic interaction effects are encoded in the self-energy which can incorporate the effects of different types of interactions, such as Coulomb repulsion U, electron-phonon coupling and Hund’s coupling J. While the self-energy results in broadening and renormalization of the electronic dispersion, the inelastic processes result in replica features related to the energy of bosonic modes.
I will discuss the effects of electron-boson coupling and self-energy in correlated materials, and show how the latter can be accounted for by introducing them in calculations of quasiparticle interference as measured by STM. I will show how the self-energy and inelastic effects affect the scattering patterns, how to extract information from them and infer on the type of interactions that dominate the tunneling process and electronic interactions in the sample.