Local structure, electronic and optical characteristics of Er³⁺-doped Y₃Sc₂Al₃O₁₂garnet: a multi-scale exploration...

In this study, the structural evolution, electronic properties, and optical characteristics of Er³⁺-doped Y₃Sc₂Al₃O₁₂(YSAG) crystals were systematically investigated by the CALYPSO structure prediction methodology combined with density functional theory. The crucial findings are detailed as follows. (1) The ground state structure of Er³⁺:YSAG was determined. Er³⁺ions substitute Y³⁺sites to form [ErO₈]^13-coordination polyhedra withD₂point group symmetry, triggering space group transitions fromIa3¯dtoC222. The phonon spectrum and x-ray diffraction simulations confirmed the stability and accuracy of the structure. (2) Er³⁺doping induced a band gap to narrow from 4.38 eV to 3.32 eV, attributed to the influence of the 4f electrons of Er³⁺ions. Electron localization function and Bader charge analyses demonstrated the predominantly ionic nature of Er-O bonds. (3) Dielectric functions and absorption coefficients specified enhanced absorption in the vacuum ultraviolet region (25-35 eV) upon Er³⁺incorporation. This study elucidated the structure-property relationships governing rare-earth doping effects in garnet-type laser crystals, providing fundamental theoretical insights for the microstructural design and performance optimization of rare-earth-doped laser materials.