Percolation‐Driven β ‐Relaxation Enables Resonant Acceleration of Crystallization in Amorphous Phase‐Change Materials

ABSTRACT Amorphous phase‐change materials enable fast and reversible switching in optical and electronic devices, yet crystallization kinetics are still controlled primarily through empirical thermal protocols. Here we identify a microscopic picture governing crystallization in the prototypical phase‐change material Ge 2 Sb 2 Te 5 , in which crystallization pathways are organized by the percolation of mobile atomic networks associated with β ‐relaxation. We show that this percolation transition distinguishes the dominance of diffusion‐driven and diffusionless nucleation and growth during crystallization processes. We further demonstrate that frequency‐selected ultrasonic excitation, applied in conjunction with heating, accelerates crystallization by enhancing percolation‐mediated atomic dynamics. This acceleration is maximized near the β ‐relaxation frequency, consistent with resonant excitation of mobile atoms. Our results establish a direct link between glassy relaxation, atomic‐scale percolation, and crystallization, and introduce a new route to modulating phase‐change kinetics through targeted excitation of fundamental glassy dynamics.