Condensed Matter Seminar - Designing Non-Equilibrium Functionalities in Quantum Materials Using Light

Quantum materials are broadly distinguished by their unique macroscopic phases, which emerge as a result of electronic interactions across many length scales. These emergent phases lead to functionalities with enormous technological potential, such as high temperature, superconductivity and multiferroicity, but devising ways to manipulate their quantum behavior "on demand" for practical applications remains a major challenge. In this talk, I will describe a methodology to engineer materials properties dynamically with ultrashort light pulses, which results in non-equilibrium states that often cannot be achieved
otherwise. We use intense, tailored, THz-frequency excitation to drive ions in the crystal lattice to large amplitudes and exploit nonlinearities to steer the various degrees of freedom of the system. This approach provides a knob to tune electronic and magnetic interactions, break symmetries, and unlock new phases. I will highlight some recent experiments demonstrating the ability to optically control, enhance, and induce magnetism and ferroelectricity in complex oxides. Interestingly, the ultrafast dynamics of these driven systems gives way, in some cases, to metastable light-induced states persisting for "ultralong" times, which form even well above the equilibrium ordering temperature. Finally,
I will touch upon our current efforts of integrating atomic layer materials synthesis to enable the rational design of non-equilibrium functionalities for next-generation quantum and ultrafast technologies.