【摘要】 用密度泛函理论平面波赝势方法及广义梯度近似研究（C₂）/（BN）_2×1超结构在高压下的电子特性和光学性质,并计算模拟其能带结构与光学性能随压强的变化规律.结果表明:随着外界压强的增大,该物质的禁带宽度略有展宽.当压强从0增至100 GPa时,禁带宽度值从2.353 e V增加到2.438 e V,相对增加值为3.48%.从态密度图上可以看出,由于（C₂）/（BN）_2×1的s轨道和p轨道杂化程度较高,该结构处于稳定状态.根据介电函数可知,随着压力的增大该物质的本征吸收限略显蓝移,这与禁带宽度随压强的增加略有增大的结果一致.从吸收系数图谱上可以看出,当波长大于248 nm后该物质是透明的,也就是说在可见光范围内（390～700 nm）,BC₄N是一种透明物质.同时,随着压强的增加,吸收系数、反射系数、能量损失谱、消光系数和折射率均出现蓝移,但图谱的形态没有明显的改变.更多还原

【Abstract】 Electronic structures and optical properties of（ C₂）/（ BN）_2×1 superlattice at high pressure have been investigated using generalized gradient approximation with the density functional theory（ DFT） plane-wave pseudopotential method. The pressure dependences of electronic band structures,the optical properties of（ C₂）/（ BN）_2×1 superlattice are predicted. It is found that the calculated band gap is slightly widened as the external-pressure increases. The value increases from 2.353 e V to 2.438 e V,and the relative band gap is 3.48%,when the pressure increases from 0 to 100 GPa. From the density of state,it can be seen that the structure is stable because of the high degree of hybridization between the s and p orbitals of the（ C₂）/（ BN）_2×1. According to the dielectric function,the eigenvalue absorption limit has slightly blue-shift with the increase of pressure,which is consistent with the small increase of the band gap. And the absorption coefficient spectra suggest that（ C₂）/（ BN）_2×1 superlattices are consistently transparent when the wavelength is longer than 248 nm,that is to say,they are transparent in the range of visible light（ 390-700 nm） under high pressure. Moreover,all of the optical spectra,such as absorption coefficient α（ ω）,reflectivity coefficient R（ ω）,energy-loss spectrum L（ ω）,the extinction coefficient k（ ω）,and refractive index n（ ω） have blue-shift as pressure increases without any notable shape changes.更多还原