Local structural power exponent as an indicator of elastic heterogeneity in glasses

The origin of the nontrivial power-law relationships between atomic packing density and the related structural properties is considered to be a key puzzle in understanding the nature of glasses. Here, we report the direct link between the medium-range structural evolution and elastic heterogeneity by systematically investigating the packing-density-dependent properties of various glasses based on extensive large-scale molecular dynamics simulations. It is shown that the power exponent of the peaks corresponding to the medium-range orders on the pair correlation function converges to the exponent of the first diffraction peak rather than the Euclidean dimension. This exponent can be regarded as an indicator of heterogeneous mechanical properties. The global power-law relationship results from intrinsic mechanical heterogeneity, with the nontrivial power-law response being a local feature. Our finding provides a different perspective on order in disordered materials and sheds some light on the structural-property relationship in glasses.