Abstract The “microstructure determines properties” paradigm applies well to crystalline materials but struggles with amorphous systems. While researchers have long sought to link amorphous structures to macroscopic properties, traditional analyses focus on geometric packing, which our study reveals as insufficient. We demonstrate this using two Pd-based metallic glasses, Pd40Cu40P20 and Pd40Ni40P20, which exhibit nearly identical geometries but different secondary relaxations. Electronic structure analysis uncovers the key distinction: Pd40Cu40P20 has weaker Cu-P bonds and a less developed covalent network, enabling string-like atomic motions that drive pronounced relaxation, while Pd40Ni40P20’s stronger Ni-P interactions create a more constrained network. These findings highlight the critical role of electronic interactions and bonding fluctuations—beyond geometry—in governing glass dynamics. By integrating experiments and deep-learning simulations, we bridge the gap between local bonding heterogeneity and macroscopic behavior, offering new design principles for amorphous materials that prioritize electronic structure over purely geometric order. This advances glass physics by emphasizing the need to incorporate chemical interactions into structural analyses.
Gao et al. (Wed,) studied this question.