基于第一性原理的赝势平面波方法,对异质外延关系为Ru2Si3 (100)//Si(001),取向关系为Ru2Si3 [010]//Si[110]正交相的Ru2Si3平衡体系下能带结构、态密度和光学性质等进行了理论计算。计算结果表明：当1.087 nm≤a≤1.099 nm时,正交相Ru2Si3的带隙值随着晶格常数a取值的增大而增大。当a取值为1.093 nm时,体系处于稳定状态,此时Ru2Si3是具有带隙值为0.773 eV的直接带隙半导体。Ru2Si3价带主要是由Si的3p,3s态电子及Ru 4d态电子构成[导带主要由Ru的4d及Si的3p态电子构成。外延稳定态及其附近各点处Ru2Si3介电函数的实部和虚部变化趋势基本一致,但外延稳定态Ru2Si3介电函数的曲线相对往低能区漂移,出现的介电峰减少且峰的强度明显增强。

We calculated the electronic structure and optical properties of semiconductor material Ru2Si3 epitaxial on Si (001) that the epitaxial relation is Ru2Si3 (100)//Si(001) with Ru2Si3 [010]//Si[110] by using the pseudo-potentials plane-wave method based on first-principles methods.As shown by the calculated results,when the lattice parameter α is between 1.087 nm with 1.099 nm,the band gap of orthorhombic Ru2Si3 increases with the increase of α.The system is in the stable conduction as well as Ru2Si3 is a direct semiconductor with the band gap of 0.773 eV when the lattice parameter is 1.093 nm.The valence bands of Ru2Si3 are mainly composed of Si 3p,3s and Ru 4d,the conduction bands are mainly composed of Ru 4d and Si 3p.The calculated real part and imaginary part of dielectric function shows that the trend of change is similar on the whole between the epitaxial stable conditions and its neighbouring points.However,the curves of epitaxial Ru2Si3 drift toward low energy and the number of dielectric function peak decreases as well as the intensity bocomes strong obviously.