de Jager Marjolein, de Jong Joris, Filion Laura
Soft Condensed Matter, Debye Institute of Nanomaterials Science, Utrecht University, Utrecht, The Netherlands.
Soft Matter. 2021 Jun 16;17(23):5718-5729. doi: 10.1039/d1sm00531f.
In this paper we use computer simulations to examine point defects in systems of "soft" colloidal particles including Hertzian spheres, and star polymers. We use Monte Carlo simulations to determine the deformation of the different crystals associated with vacancies and interstitials and use thermodynamic integration to predict the equilibrium concentrations of such defects. We find that the nature of the lattice distortion is mainly determined by the crystal structure and not by the specifics of the interaction potential. We can distinguish one-, two-, and three-dimensional lattice distortions and find that the range of the distortion generally depends on the dimensionality. We find that in both model systems the deformation of the body-centered cubic (BCC) crystal caused by an interstitial is one-dimensional and we show that its structure is well described as a crowdion. Similarly, we show that the one-dimensional deformation of the hexagonal (H) crystal of Hertzian spheres caused by a vacancy can be characterized as a voidion. Interestingly, with the exception of the FCC crystal in the Hertzian sphere model, in all cases we find that the interstitial concentration is higher than the vacancy concentration. Most noteworthy, the concentration of interstitials in the BCC crystals can reach up to 1%.
在本文中，我们使用计算机模拟来研究包括赫兹球和星形聚合物在内的“软”胶体粒子系统中的点缺陷。我们使用蒙特卡罗模拟来确定与空位和间隙原子相关的不同晶体的变形，并使用热力学积分来预测此类缺陷的平衡浓度。我们发现晶格畸变的性质主要由晶体结构决定，而非相互作用势的具体细节。我们可以区分一维、二维和三维晶格畸变，并发现畸变的范围通常取决于维度。我们发现，在这两个模型系统中，间隙原子引起的体心立方（BCC）晶体的变形都是一维的，并且我们表明其结构可以很好地描述为挤列子。同样，我们表明，空位引起的赫兹球六方（H）晶体的一维变形可以表征为空列子。有趣的是，除了赫兹球模型中的面心立方（FCC）晶体外，在所有情况下我们都发现间隙原子浓度高于空位浓度。最值得注意的是，BCC晶体中间隙原子的浓度可达1%。
