CdGeAs_2晶体红外双折射率和吸收系数的第一原理计算

The first-principle calculation of infrared birefringence and absorption of CdGeAs_2 crystal

基于第一原理赝势平面波方法,采用密度泛函理论的局域密度近似(LDA)方法计算了CdGeAs_2晶体的介电函数,并由此得到红外波段的折射率n_e、n_o,双折射率△n和静态介电常数ε(0),将计算值同实验值作比较,结果一致.还计算了CdGeAs_2晶体的红外吸收系数,与实验测得的红外透过率谱进行了比较,计算值与实验值吻合较好.结果对CdGeAs_2晶体质量的改进和应用具有实用价值.

Using local density approximation （LDA） within the first-principles of plane wave pseudo-potential method based upon the density function theory （DFT）, the dielectric function of CdGeAs2 crystal was calculated. The infrared refractive index he, no, birefringence An and static dielectric constant e（0） were obtained. The calculated results were in agreement with the experimental values. The IR-absorption of CdGeAs2 crystal was also calculated. The calculated values and the experimental IR-transmittance were compared and matched well. The results have practical values in CdGeAs2 crystal＇s quality improvement and application.