First-principles study of optical properties of yttrium-aluminum garnet under high pressure

the first-principles method based on density functional theory (DFT) is used to calculate the optical properties of yttrium aluminum garnet crystal without and with oxygen-vacancy defects in the pressure range of 0-120 GPa. The data obtained show that: (1) within 120 GPa, there is no light absorption (transparency) in the visible region for the perfect crystal and defective crystal with 2 + charged oxygen vacancy (with lowest formation energy), and (2) the pressure loading will lead to a decrease in the peak intensity of its reflection spectrum, and the presence of the vacancy defect will makes the peak intensity is further reduced. These results may be important for further experimental study. (authors)