Rino José Pedro, Borges Denilson, Mota Rita C, Silva Maurício A P
Departamento de Física, Universidade Federal de São Carlos, 13565-905 São Carlos, São Paulo, Brazil.
J Chem Phys. 2008 May 14;128(18):184704. doi: 10.1063/1.2918268.
Molecular dynamics studies of structural and dynamical correlations of molten and vitreous states under several conditions of density and temperature were performed. We use an effective recently proposed interatomic potential, consisting of two- and three-body covalent interactions which has successfully described the structural, dynamical, and structural phase transformation induced by pressure in ZnTe [D. S. Borges and J. P. Rino, Phys. Rev. B 72, 014107 (2005)]. The two-body term of the interaction potential consists of Coulomb interaction resulting from charge transfer, steric repulsion due to atomic sizes, charge-dipole interaction to include the effect of electronic polarizability of anions, and dipole-dipole (van der Waals) interactions. The three-body covalent term is a modification of the Stillinger-Weber potential. Molecular dynamics simulations in isobaric-isenthalpic ensemble have been performed for systems amounting to 4096 and 64 000 particles. Starting from a crystalline zinc-blende (ZB) structure, the system is initially heated until a very homogeneous liquid is obtained. The vitreous zinc telluride phase is attained by cooling the liquid at sufficiently fast cooling rates, while slower cooling rates lead to a disordered ZB crystalline structure. Two- and three-body correlations for the liquid and vitreous phases are analyzed through pair distribution functions, static structure factors, and bond angle distributions. In particular, the neutron static structure factor for the liquid phase is in very good agreement with both the reported experimental data and first-principles simulations.
我们进行了在几种密度和温度条件下熔融态和玻璃态的结构与动力学相关性的分子动力学研究。我们使用了最近提出的一种有效原子间势，它由两体和三体共价相互作用组成，已成功描述了ZnTe中压力诱导的结构、动力学和结构相变[D. S. Borges和J. P. Rino，《物理评论B》72，014107(2005)]。相互作用势的两体项由电荷转移产生的库仑相互作用、原子尺寸引起的空间排斥、包含阴离子电子极化率效应的电荷 - 偶极相互作用以及偶极 - 偶极（范德华）相互作用组成。三体共价项是对Stillinger - Weber势的修正。我们在等压 - 等焓系综中对包含4096和64000个粒子的系统进行了分子动力学模拟。从闪锌矿（ZB）晶体结构开始，系统首先被加热直至获得非常均匀的液体。通过足够快的冷却速率冷却液体可得到玻璃态碲化锌相，而较慢的冷却速率会导致无序的ZB晶体结构。通过对分布函数、静态结构因子和键角分布分析了液相和玻璃相的两体和三体相关性。特别是，液相的中子静态结构因子与已报道的实验数据和第一性原理模拟都非常吻合。
