Structural heterogeneity and medium-range order in Zr_xCu_100−x metallic glasses

Realistic three-dimensional atomistic structures of Zr_xCu_100−x (x=35,50) bulk metallic glasses are constructed using a combination of x-ray diffraction experiment and computational modeling. A cluster correlation method is developed to analyze the medium-range order in amorphous systems. We show that the glass systems consist of a stringlike backbone network formed by icosahedral clusters and a liquidlike structure filling in the remaining space. These findings are consistent with those obtained from our independent classical molecular-dynamics studies with embedded-atom method potential for ZrCu system. Such a heterogeneous structure provides a fundamental structural perspective of dynamical heterogeneity and glass formation.