第一性原理研究KDP晶体中Ba取代K点缺陷

First principles study on point defect of Ba substituting for K in KDP crystals

用基于第一性原理的CASTEP模拟了Ba替代K缺陷前后形成的电子结构和能态密度。发现晶体能带宽度降至6.4 eV左右,对应着380 nm的双光子吸收,这一结果可以解释掺Ba晶体在紫外波段的吸收现象。Ba替代K点缺陷仅使其周围的晶格及电子结构发生轻微畸变,对晶体整体结构影响不大。

The electronic structure and energy state density of Ba substituting for K in KDP crystals was studied by first principles calculations.The point defect narrows down the energy gap to about 6.3 eV,which corresponds to a two-photon absorption of 390 nm.This can explain the absorption of Ba-doped KDP crystals in ultraviolet（UV） region.Moreover,the defect only makes the surrounding crystal lattice and electronic structure slightly distorted,and thus little impact is placed on the overall structure of the crystal.