A universal origin for secondary relaxations in supercooled liquids and structural glasses

作者：Stevenson Jacob D; Wolynes Peter G^*

来源：Nature Physics, 2010, 6(1): 62-68.

DOI：10.1038/NPHYS1432

Supercooled liquids and glasses show a range of relaxation times. Nearly all glass-forming liquids show secondary relaxations, high-frequency dynamical modes of structural reconfiguration seemingly distinct from the primary alpha relaxations. We show that accounting for driving-force fluctuations and the diversity of reconfiguring shapes in the random first-order transition theory yields a new dynamical process that shares many of the features ascribed to secondary relaxations. Whereas primary relaxation takes place through activated events involving compact regions, secondary relaxation is governed by more ramified, string-like or percolation-like clusters of particles. These secondary relaxations generate a low free-energy tail on the distribution of activation barriers, which becomes more prominent with increasing temperature. T

• 出版日期2010-1