二维硼结构中条带状空位长程有序分布的理论研究  

Theoretical study of long-range ordered vacancy distribution in two-dimensional boron structures

作　　者：徐诗涵 何长春 杨小宝 Xu Shi-Han;He Chang-Chun;Yang Xiao-Bao(School of Physics and Optoelectronic Engineering,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学物理与光电学院,广州510640

出　　处：《物理学报》2024年第9期216-222,共7页Acta Physica Sinica

基　　金：广州基础与应用基础研究项目(批准号:202201010090)资助的课题.

摘　　要：在二维硼结构中,有序分布的高浓度空位可以增强其结构的稳定性,并对材料性能产生显著影响.根据最近的实验进展,本文重点关注二维硼结构中空位呈条带状分布的体系,提出有效模型系统研究结构稳定性随空位分布的变化.结合第一性原理计算结果,对空位不同近邻作用参数进行拟合,预测了不同空位浓度的稳定结构,发现在该体系中空位不同近邻存在竞争,导致长周期分布的趋势,揭示了不同近邻作用的相互竞争导致长周期结构稳定存在的关键机制.In a two-dimensional boron structure,the ordered high-concentration vacancy distribution can enhance structural stability and significantly modulates material properties.Based on recent experimental progress,herein we particularly focus on the two-dimensional boron structures with a striped distribution of hexagonal vacancies,in order to explore the formation of long-period boron structures.Utilizing the structures of alloy generation and recognition(SAGAR)program developed by our group,we eliminate duplicate structures according to the structural symmetry to reduce computational cost.An effective model system is proposed to investigate the effect of vacancy distribution on the stability of the system,where the interactions between vacancies are utilized for estimating the total energy.By selecting structures with appropriate concentrations and combining first-principles calculations,the parameters in the model are fitted for different vacancy neighbor interactions,which can be further used to predict stable structures at various vacancy concentrations.The feasibility of model analysis is emphasized for structural screening,showing the good agreement between the parameterized model and the first-principles calculations.Interestingly,under the same vacancy concentration,stable boron structures with different cell sizes exhibit distinct vacancy distributions,indicating a trend of long-period distribution for ground state structures.To address this phenomenon,when the stable candidate structures from the 1/6 series are dominant in number within the computable range and the changes in neighbor statistics can be clearly seen,we select the structures from this concentration series for detailed calculations.The calculation results indicate that the convergence of the average energy is primarily influenced by the interaction between the fourth nearest neighbor and the sixth nearest neighbor.When considering only these two neighbors,the system energy changes with the increase of cell size as follows:the average energy of

关 键 词：二维硼结构 长周期结构 空位分布 第一性原理计算 

分 类 号：O469[理学—凝聚态物理]