Data for: Photoinduced correlations in stochastic dynamics of a solid-state ionic conductor

Photoexcitation by ultrashort laser pulses plays a crucial role in
controlling reaction pathways, creating nonequilibrium material
properties, and offering a microscopic view of complex dynamics at the
molecular level. The photo response following a laser pulse is, in
general, non-identical between multiple exposures due to spatiotemporal
fluctuations in a material or the stochastic nature of dynamical pathways.
However, most ultrafast experiments using a stroboscopic pump-probe scheme
struggle to distinguish intrinsic sample fluctuations from extrinsic
apparatus noise, often missing seemingly random deviations from the
averaged shot-to-shot response. Leveraging the stability and high photon
flux of time-resolved X-ray micro-diffraction at a synchrotron, we
employed established statistical tools to quantitatively characterize the
stochastic behavior of the photoinduced dynamics in a solid-state
electrolyte. By analyzing temporal evolutions of the lattice parameter of
a single grain in a powder ensemble, we found that the sample responses
after different shots contain random fluctuations that are, however, not
independent. Instead, there is a correlation between the nonequilibrium
lattice trajectories following adjacent laser shots with a characteristic
correlation length of approximately 1,500 shots, which represents an
energy barrier of 0.4 eV for switching the photoinduced pathway, a value
that is close to the activation energy of lithium ion diffusion. Not only
does our nonequilibrium noise correlation spectroscopy provide insights
for studying fluctuations that are central to phase transitions in both
condensed matter and molecular systems, but it also paves the way for
discovering novel metastable states buried in oft-presumed random,
uncorrelated fluctuating dynamics.