Discovery of a paired Gaussian and long-tailed distribution of potential energies in nanoglasses

It is generally believed that the intrinsic properties of glasses are intimately related to potential-energy landscapes (PELs). However, little is known about the PELs of glasses below the glass transition temperature (T-g). Taking advantage of lower potential-energy barriers in nanosystems, we have systematically investigated the dynamics behavior of two nanoglasses, Al-43 and Al-46. Structure transformation is identified in our pure molecular-dynamics simulation far below T-g, which manifests the existence of metabasins in PELs, at least for nanoglasses. Surprisingly, we find that the distribution of potential energies shows a paired Gaussian and long-tailed distribution at temperatures below and approaching T-g; correspondingly, the distribution of the alpha-relaxation time exhibits an exponential-like decay. In contrast to the Gaussian distribution of energy in typical liquids and solids, the unexpected distribution may reflect the intrinsic feature of nanoglasses. Associated with the exponential-like distribution of the alpha-relaxation time, the stretched-exponential structural relaxation is found, and the maximum stretched behavior appears around T-g. Despite our studies focused on nanoglasses, the current finding may shed light on future studies of bulk glasses.

Automated summary

This article systematically investigates the dynamics behavior of nanoglasses and reveals the presence of structure transformation and metabasins below the glass transition temperature. The distribution of potential energies and alpha-relaxation time exhibits unique characteristics, indicating the intrinsic features of nanoglasses.