Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8571, Japan.
Phys Rev Lett. 2011 Jan 7;106(1):015701. doi: 10.1103/PhysRevLett.106.015701. Epub 2011 Jan 4.
We numerically investigate the dynamical properties of the one-component Gaussian core model in supercooled states. We find that nucleation is increasingly suppressed with increasing density. The system concomitantly exhibits glassy, slow dynamics characterized by the two-step stretched exponential relaxation of the density correlation and a drastic increase of the relaxation time. We also find a weaker violation of the Stokes-Einstein relation and a smaller non-Gaussian parameter than in typical model glass formers, implying weaker dynamic heterogeneities. Additionally, the agreement of the simulation data with the prediction of mode-coupling theory is exceptionally good, indicating that the nature of the slow dynamics of this ultrasoft particle fluid is mean-field-like. This fact may be understood as a consequence of the long-range nature of the interaction.
我们通过数值模拟研究了过冷状态下单组分高斯核模型的动力学性质。我们发现,随着密度的增加,成核越来越受到抑制。同时,体系表现出玻璃态、缓慢动力学特征,表现为密度相关函数的两步拉伸指数松弛和弛豫时间的急剧增加。我们还发现,与典型的模型玻璃形成体相比,Stokes-Einstein 关系的违反程度较弱,非高斯参数较小,这意味着动态异质性较弱。此外,模拟数据与模式耦合理论的预测非常吻合,表明这种超软粒子流体的慢动力学性质具有平均场特征。这一事实可以理解为相互作用的远程性质的结果。