Light-induced emergent phenomena in nonequilibrium states
Dr. Yijing Huang
IQUEST Fellow
UIUC
Dr. Yijing Huang will discuss how light induces emergent phenomena in nonequilibrium states. In particular, she will show the path to creating new order and new excitations that have no counter parts in equilibrium.
Creating new order: In the resonantly bonded material SnSe, which has a high structural tunability, Dr. Huang revealed a novel lattice instability by using femtosecond time-resolved X-ray diffraction. This approach allowed her to reconstruct the nonequilibrium lattice structure, pointing towards a higher-symmetry configuration not observed in equilibrium. Further, she investigated the excited-state phonon dispersion in SnSe through time-resolved X-ray diffuse scattering, offering insights into how photoexcitation alters specific bond strengths, driving the observed lattice instability.
Creating new excitations: In an out-of-equilibrium chiral crystal tellurium, Dr. Huang found a dynamic magneto-chiral instability manifested as an amplified response in THz emission. This instability is similar to the known instability in chiral plasmas, such as a quark gluon plasma in heavy ion collisions. However, our observed dynamic magneto-chiral instability is new, it is radiative, and couples to dipoles, forming polaritons. And it is the first time it is discussed in a chiral crystal.
Hosted by Prof. Xia. Liu