压力对有序Li_(1/2)TiS_2光学性质的影响

Influence of Pressure on Optical Properties of Li_(1/2)TiS_2

采用第一性原理的平面波赝势方法和局域密度近似(LDA),计算了压力对Li1/2TiS2的形成能和光学性质的影响。研究发现,Li1/2TiS2体系在压强为3 GPa时形成能最小,体系最稳定,之后体系的形成能随压力的增大而单调增大;随着压力的增大,导带向高能移动而价带向低能方向移动,体系费米能级上的态密度增大,各个态密度峰值降低且数目增多;光学参量峰值的位置与介电函数虚部的峰值位置很接近,随着压力增大,均向高能方向移动(蓝移),且峰值升高。

Using local density approximation （LDA） to density functional theory, the effect of pressure on formation energy and the optical properties of Li1/2TiS2 has been studied. The results show that the formation energy reached the minimum at 3 GPa. As the pressure increases,the conduction band blue shift while the valence band red shift; the density of states at the Feruli level increases. The positions of peaks of spectrum are closed to that of the imaginary part of dielectric function. And the peaks increased with the increasing of the pressure.