Condensed-Matter Physics & Materials Science Seminar

The interaction of intense ultrafast electromagnetic fields with matter brings about many interesting phenomena. One of them is high harmonic generation (HHG), which has been extensively harnessed in the past decade to interrogate the structure and dynamics of atoms, molecules, and, more recently, solids, on a (sub-)femtosecond time scale. Focusing on the paradigmatic 3D topological insulator Bi2Se3, in the first part of my talk I will show how HHG using circularly-polarized driving fields provides a route to probe the topology of the band structure as well as the manifestations of spin-orbit interaction. The second part will be devoted to the topic of engineering effective many-body interactions in correlated systems using ultrafast light. Employing time-resolved x-ray absorption spectroscopy, I will demonstrate that intense femtosecond pulses can induce a substantial transient renormalization of the Hubbard-U parameter in a representative cuprate superconductor La2-xBaxCuO4. This result has far-reaching implications for the control of superconductivity and magnetism in light-driven quantum materials.