CrI_3高压相变及其光学性质理论研究

利用第一性原理计算方法,探讨了体相CrI_3在低温斜方六面体结构(■,BiI_3-type)及高压单斜结构(C2/m,AlCl_3-type)的相变、电子结构和光学性质.计算结果显示,半导体CrI_3当压强增加到26.1GPa时,高压导致的晶格畸变致使CrI_3从相■变化到相C2/m;原子之间的错位位移,使导带处的能带发生下移,价带处的能带发生了一定程度的上移,导致带隙减小.两种相的光学性质进一步验证了这些特性.

Theoretical study on high pressure phase transformation

Applying the first-principles calculation method, we have discussed the phase transition, electronic and optical propertie of solid phase CrI3 with low-temperature structure of rhombohedral ( ,BiI3-type) and high-pressure structure of monoclinic ( ,AlCl3-type). Calculations indicate when the pressure of semiconductor metal CrI3 increases to 26.1 Gpa, the lattice distortion induced by high pressure leads to the structural transformation of CrI3 from phase to phase .Dislocation displacement between atoms lead to the decrease of band gap, the energy band of the conduction move down and the the valence band move up at a certain extent. The optical peculiarity of the two phases verified these properties further.