Pressure-induced Structural Crossover in a Zr65Ni35 Metallic Glass

The local atomic structure has long been recognized as a predominant characteristic and key to understanding glassy structures and properties. However, the factors governing the formation and evolution of these structures in metallic glasses remain elusive. Herein, we report an unexpected local structural crossover under pressure in a simple binary ${\mathrm{Zr}}_{65}{\mathrm{Ni}}_{35}$ metallic glass consisting of pure transition metals, evidenced by in situ high-pressure synchrotron x-ray diffraction and electrical resistivity measurements combined with ab initio molecular dynamics simulations. While the specific volume of the metallic glass (MG) follows a single-phase compression behavior without an apparent volume collapse, detailed analysis of the structural properties using structure factor, reduced pair-distribution function, and simulations reveals sharp changes of the Ni-centered clusters at \ensuremath{\sim}20 GPa in terms of their coordination numbers, atomic pair distances, and Voronoi polyhedra. This structural crossover is found to be closely linked to the enhanced contribution of the Ni $d$ orbital to the electron density of state at the Fermi level under high pressures. These results underscore the correlation between the local atomic structure and the intricate electronic structure, particularly the $3d$ electronic structure, in transition-metal MGs, which sheds light on the stability characteristics of local structures in MGs from an electronic structure point of view.