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

Article

关键词: GLASS-TRANSITION;    SPATIAL CORRELATIONS;    LANDSCAPE;    LIQUIDS;    MODEL;    COOPERATIVITY;    HETEROGENEITY;    TEMPERATURE;    RELAXATION;    BEHAVIOR;   

DOI  :  10.1103/PhysRevB.105.035403

来源: SCIE

【 摘 要 】

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.

【 授权许可】

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