Non-monotonic response of a strongly coupled lead-halide perovskite lattice under localized kinetic thermal-pulse excitation

We investigate the nonequilibrium response of a strongly coupled hybrid lead-halide perovskite model subjected to an idealized localized kinetic thermal pulse. In the revised manuscript, the word “driving” refers specifically to velocity-rescaling within a finite spherical region, not to explicit optical excitation, carrier injection, or an applied electric field. By combining local–global structural correlations with time-resolved dynamical observables, velocity-seed ensembles, independent equilibrated configurations, and local-region-size sensitivity tests, we show that the redistribution-based structural response is not a simple monotonic function of pulse strength. Instead, intermediate excitation produces enhanced local structural reconfiguration while large-scale disorder remains limited, whereas stronger excitation produces a high-disorder saturation response. Additional Pb–X coordination, bond-length, angular-variance, and octahedral-distortion descriptors confirm that this conclusion is not an artifact of a single RDF-derived metric. The resulting picture should be interpreted as an operational nonequilibrium crossover between response regimes rather than a thermodynamic phase transition. These results establish a conservative framework for identifying spatially selective structural responses in driven, anharmonic lattice models.