Sep 19, 2019 3:45 pm - Nielsen Hall 170 - Colloquium
Mateo Mitrano - Illinois
Controlling quantum materials with light

Ultrashort optical pulses, especially when resonant to specific lattice modes, have recently emerged as a powerful means to control solids and their phase transitions. In this talk, I will discuss the possibility to manipulate the lattice and electrons to bring about nonequilibrium superconductivity at temperatures far above the ordinary thermodynamic critical temperature Tc. I will focus on the specific example of the BCS-like superconductor K3C60, in which ultrafast midinfrared excitation of vibrational modes lead to an emergent nonequilibrium superconducting-like phase above its equilibrium Tc. This light-induced state can be suppressed by external pressure, as expected for a conventional BCS superconductor, but its microscopic origin is still unclear. In order to further our understanding of these dynamics, it is necessary to go beyond ultrafast optics and instead probe electronic excitations at the atomic scale. To this end, I will report the development of next-generation time-resolved X-ray scattering methods, which enabled probing collective charge-order dynamics in a cuprate superconductor, and will lead to the observation of novel nonlinear effects in quantum materials.