Relaxation in a glassy binary mixture: Mode-coupling-like power laws, dynamic heterogeneity, and a new non-Gaussian parameter

@article{citeulike:2764121, abstract = {We examine the relaxation of the Kob-Andersen Lennard-Jones binary mixture using Brownian dynamics computer simulations. We find that in accordance with mode-coupling theory the self-diffusion coefficient and the relaxation time show power-law dependence on temperature. However, different mode-coupling temperatures and power laws can be obtained from the simulation data depending on the range of temperatures chosen for the power-law fits. The temperature that is commonly reported as this system's mode-coupling transition temperature, in addition to being obtained from a power law fit, is a crossover temperature at which there is a change in the dynamics from the high-temperature homogeneous, diffusive relaxation to a heterogeneous, hopping-like motion. The hopping-like motion is evident in the probability distributions of the logarithm of single-particle displacements: approaching the commonly reported mode-coupling temperature these distributions start exhibiting two peaks. Notably, the temperature at which the hopping-like motion appears for the smaller particles is slightly higher than that at which the hopping-like motion appears for the larger ones. We define and calculate a new non-Gaussian parameter whose maximum occurs approximately at the time at which the two peaks in the probability distribution of the logarithm of displacements are most evident.}, author = {Flenner, Elijah and Szamel, Grzegorz }, citeulike-article-id = {2764121}, doi = {10.1103/PhysRevE.72.011205}, journal = {Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)}, number = {1}, posted-at = {2008-05-07 08:18:38}, priority = {2}, publisher = {APS}, title = {Relaxation in a glassy binary mixture: Mode-coupling-like power laws, dynamic heterogeneity, and a new non-Gaussian parameter}, url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal\&id=PLEEE8000072000001011205000001\&idtype=cvips\&gifs=yes}, volume = {72}, year = {2005} }

TY - JOUR ID - citeulike:2764121 TI - Relaxation in a glassy binary mixture: Mode-coupling-like power laws, dynamic heterogeneity, and a new non-Gaussian parameter JF - Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) VL - 72 IS - 1 PB - APS N2 - We examine the relaxation of the Kob-Andersen Lennard-Jones binary mixture using Brownian dynamics computer simulations. We find that in accordance with mode-coupling theory the self-diffusion coefficient and the relaxation time show power-law dependence on temperature. However, different mode-coupling temperatures and power laws can be obtained from the simulation data depending on the range of temperatures chosen for the power-law fits. The temperature that is commonly reported as this system's mode-coupling transition temperature, in addition to being obtained from a power law fit, is a crossover temperature at which there is a change in the dynamics from the high-temperature homogeneous, diffusive relaxation to a heterogeneous, hopping-like motion. The hopping-like motion is evident in the probability distributions of the logarithm of single-particle displacements: approaching the commonly reported mode-coupling temperature these distributions start exhibiting two peaks. Notably, the temperature at which the hopping-like motion appears for the smaller particles is slightly higher than that at which the hopping-like motion appears for the larger ones. We define and calculate a new non-Gaussian parameter whose maximum occurs approximately at the time at which the two peaks in the probability distribution of the logarithm of displacements are most evident. AU - Flenner, Elijah AU - Szamel, Grzegorz PY - 2005/// UR - http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PLEEE8000072000001011205000001&idtype=cvips&gifs=yes ER -