稀土四硼化物表面性质的第一性原理研究  

First principles study on surface properties of rare earth tetraborides

作　　者：韩星 王健[1] 何志军 邱东超[1] HAN Xing;WANG Jian;HE Zhijun;QIU Dongchao(School of Science,University of Science and Technology Liaoning,Anshan 114051,China)

机构地区：[1]辽宁科技大学理学院,辽宁鞍山114051

出　　处：《辽宁科技大学学报》2022年第3期215-220,240,共7页Journal of University of Science and Technology Liaoning

基　　金：国家自然科学基金(51874171);辽宁省教育厅项目(LJKZ0321);辽宁科技大学优秀人才项目(2018RC01)。

摘　　要：电子发射材料的性能通常与功函数和表面稳定性有关。本文利用基于密度泛函理论的第一性原理,计算五种四硼化物(RB,R为稀土金属La、Ce、Gd、Tb、Dy)的功函数和表面能。计算表明,RB表面性质取决于晶体表面取向和终结面原子。当终结面为稀土原子时,等化学计量和非化学计量表面的功函数和表面能都会降低。其中功函数降低约1.5 eV,非化学计量比的表面能平均降低0.3 J/m~2。LaB的理论发射性能最好,是一种潜在的新型电子发射材料。The properties of an electron-emitting material are usually related to its work function and surface stability. In this paper,the work functions and surface energies of five tetraborides(RB,R for rare earth metals La,Ce,Gd,Tb,Dy) were calculated using the first principles based on density functional theory. The calculations show that the surface properties of the RBdepend on the crystal surface orientation and the end-surface atoms. The work functions and surface energies of both the stoichiometric and non-stoichiometric surfaces decreased when the end-surface atoms were the rare earth atoms. The work function reduced by about 1.5 eV and the surface energy of non-chemical stoichiometric ratio reduced by 0.3 J/m~2. The LaBhas the best theoretical emission performance,which makes it a potential new electron-emitting material.

关 键 词：四硼化物 第一性原理 功函数 表面能 

分 类 号：O485[理学—固体物理]