CQS Seminar: Ultrafast Symmetry Control In Crystalline Materials With Light

The interplay between structure, symmetry, and function is a fundamental and long-standing paradigm in physics, dictating our access to physical properties, revealing hidden order, and guiding the search for, and engineering of, new physical phenomena. Condensed matter has served as an important testbed for exploring this connection due to its experimental accessibility. But crystalline solids are often constrained by their chemistry to only one or a few structural phases, restricting the range of physical properties that can be explored or engineered.

The recent development of bright, tunable mid- and far-infrared laser sources presents an opportunity for tailored structural control of materials on ultrafast (sub-picosecond) timescales. These laser sources enable the rapid conversion of optical energy into coherent mechanical energy through direct excitation of phonons – the mechanical modes of crystals. Accompanying this mechanical response, striking changes to fundamental condensed phase properties have been reported, including alteration, enhancement, and control of metallicity, magnetism, polarization, and superconductivity.

In this talk, I will discuss our theoretical exploration of light-driven symmetry control in crystalline materials via direct excitation of phonons. I will show that the direct drive of phonons in condensed phases provides a strategy to induce new symmetries and length scales, prepare chemical environments not previously achievable near equilibrium, and traverse known or hidden phase boundaries, setting the stage for this nascent field to have lasting impact on the out-of-equilibrium design of materials and our understanding of the connection between structure, symmetry, and function.

Hope you can make it!