液态Ga-In合金中的团簇分离现象

与以往试验及模拟计算方法不同,文章利用从头计算分子动力学研究了液态Ga, In及Ga-In合金的偏结构. 发现合金偏双体相关函数gGaGa(r), gInIn(r)的第一峰的位置分别与液态纯Ga和纯In的第一峰 位置接近, gGaIn(r)第一峰位置大于纯Ga和纯In第一峰位置的平均值,说明液态Ga-In合金中异类原子 呈现排斥倾向, Ga-Ga, In-In团簇更容易出现.在纯Ga, 纯In中占据最高含量的1311键对在液态合金中占主导 地位,说明Ga-Ga, In-In团簇共存于液态Ga-In合金中. Voronoi多面体分析发现,随着In含量的增加, 在Ga_100-xIn_x(30 ≤x≤qslant 50 at.% ) 区域内, Ga原子周围主配位数出现突变,由12降为10,证明Ga-Ga和In-In团簇倾向于分离.该研究结果不同于 通常的微观不均匀模型,揭示了液态Ga-In合金中团簇分离的机制.

Cluster separation phenomena in liquid Ga-In alloys

Different from the previous experimental and simulating methods,ab initio molecular dynamics simulations are performed to investigate the partial structures of liquid Ga,In and Ga-In alloys.In liquid Ga-In alloys,the positions of first peaks in gGaGa（r） and gInIn（r） are close to those of the pure Ga and In,respectively,and the position of first peak in gGaIn（r） is larger than the average value of pure Ga and In,indicating that inhomogeneous atoms are prone to be repulsed and Ga-Ga and In-In clusters are easy to emerge in the system.The most popular 1311 pair bonds existing in liquid pure Ga and In are dominant in liquid alloys,proving that Ga-Ga and In-In clusters coexist in liquid Ga-In alloy.Through the Voronoi analysis,with In increasing,in the Ga_100-xIn_x（30≤x≤50 at.%） region,the main coordination number around Ga atoms abruptly decrease from 12 to 10,proving that Ga-Ga and In-In clusters are prone to be separated.These results are different from those obtained from the micro-inhomogeneous model and reveal the mechanism of cluster separation in liquid Ga-In alloy.