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利用基于密度泛函理论(DFT)的广义梯度近似(GGA)研究Na_2MgSn的电子结构、化学键、弹性和光学性质。能带结构显示Na_2MgSn为间接带隙材料,带隙宽度为0.126 eV;态密度和分态密度计算结果表明,费米能级附近的态密度主要来自Na、Mg和Sn的p态电子;布居分析表明Na_2MgSn中的化学键具有以共价性为主的混合离子-共价特征。计算得到Na_2MgSn的晶格参数、体模量、剪切模量和单晶的弹性常数,由此导出弹性模量和泊松比。结果表明,Na_2MgSn是力学稳定的,且具有一定的脆性。光学函数表明Na_2MgSn是好的介电材料,反射谱在6.24~10.29 eV的能量范围内,Na_2MgSn是较好的被覆材料。
Electronic structure, chemical bond, elasticity and optical properties of Na_2MgSn were studied by using generalized gradient approximation (GGA) based on density functional theory (DFT). The band structure shows that Na_2MgSn is an indirect bandgap material with a bandgap width of 0.126 eV. The calculated density of states and the calculated density of states indicate that the density of states near the Fermi level mainly comes from the p-state electrons of Na, Mg and Sn. The analysis shows that the chemical bonds in Na_2MgSn have the characteristics of covalent ion - covalent. The lattice parameters, bulk modulus, shear modulus and single crystal elastic constants of Na_2MgSn were calculated, and the elastic modulus and Poisson’s ratio were derived. The results show that Na 2 MgSn is mechanically stable and has some brittleness. The optical function shows that Na_2MgSn is a good dielectric material, the reflection spectrum is in the energy range of 6.24-10.29 eV, and Na_2MgSn is a better coating material.