3:45–4:45 pm
GCIS W301/W303 929 E. 57th Street
Abstract
Phase transitions instigated by an intense, ultrashort laser pulse usher in a new era for engineering quantum materials at the femto- (10‑15) to pico-second (10‑12 s) timescales. In this talk, I will discuss two important pathways for manipulating nonequilibrium phases of matter that feature (i) competing orders, and (ii) strong electronic interactions. More specifically, an ultrashort light pulse can (i) unleash a hidden order that is suppressed in equilibrium due to phase competition, and (ii) change the dimensionality of an ordered state by modifying excitonic correlations. I will explain the microscopic mechanisms behind these unconventional light-induced states, highlighting the roles of photoinduced topological defects, order parameter fluctuation, and carrier screening. These points will be discussed using examples from materials that exhibit a charge density wave—a spontaneous formation of electron density modulation accompanied by a periodic lattice distortion—which serves as a model system to illustrate general principles underlying ultrafast light-matter interaction in strongly correlated materials.