【摘要】 使用基于密度泛函理论的第一性原理平面波赝势法,研究了Nb二维单层原子薄片的结构稳定性和电子结构性质.对其所有的二维晶格结构的计算表明,由于Jahn-Teller效应,对称性较高的正方和六角晶格都是不稳定的二维结构.而稳定的二维结构是由对称性较高的六角晶格畸变后形成的对称性较差的斜方和中心长方结构.Nb单层原子薄片不能形成长方晶格结构.通过计算电子结构和Jahn-Teller效应,进一步讨论了这些结构的相对稳定性以及各二维晶格结构的电子能带和态密度等性质.更多还原

【Abstract】 The structural stability and electronic structures of Nb planar atomic sheets are studied by employing first-principles plane wave pseudopotential method based on the density functional theory. The calculations for all the 2-dimensional lattice structures show that, as a result of Jahn-Teller effect, the high-symmetry square and hexagonal two-dimensional structures are metastable. The most stable structures are the low-symmetry oblique and centered rectangular structures, which are the distorted structures of the hexagonal 2-D structure due to Jahn-Teller effect. The 2-D rectangular structure of Nb atomic sheet can not be formed. The relative structural stabilities, the electronic energy bands and the density of states are discussed based on the ab initio calculations and the Jahn-Teller effect.更多还原