Light-Induced Metastability in a Cuprate Ladder

Intense ultrashort lasers are an extremely effective tool for controlling the properties of quantum materials and inducing emergent states with novel functionalities. Some of the most spectacular light-induced phenomena, such as superconducting-like phases, transient charge density wave ordering, and excitonic condensation, are found to occur in materials dominated by strong electronic correlations with a large susceptibility to external stimuli. A key priority is to stabilize these effects to timescales far beyond the duration of the external excitation with the goal to better understand their microscopic physics and provide a path towards their functionalization. In this talk, I will focus on the problem of electronic metastability in Mott insulators, where prethermal and metastable electronic distributions are necessary for the emergence of novel phenomena such as eta-pairing condensation and light-driven superconductivity. By studying a paradigmatic system, the cuprate ladder compound Sr₁₄Cu₂₄O₄₁, I will demonstrate the presence of a metastable electronic charge separation enabled by a transient symmetry breaking phenomenon. Further, I will illustrate how ultrafast x-ray spectroscopy enables interrogating the microscopic charge and spin dynamics of the metastable phase with unprecedented detail.