Relaxation Energy as a Descriptor for Quick Evaluation of Dopability in Defect Engineering of Materials: Application to Dopant Screening in Lu₂SiO₅

The development of scintillation materials often requires significant efforts in defect engineering. A quick screening approach of the possible dopant elements is urgently needed. Lu 2 SiO 5 (LSO) is a scintillation material with wide applications in nuclear medicine, public security, and high‐energy physics. Ca doping and Al doping have been demonstrated to enhance the scintillation properties of Ce‐doped LSO. To further carry out such an approach, it is expected to use first‐principles calculations to assist the defect engineering. Unfortunately, the direct calculation of defect formation energy is a complicated process. Herein, the use of the relaxation energy of a dopant in the host lattice as a descriptor for the defect formation energy is proposed. It is suited for high‐throughput calculations. 32 elements are selected for doping LSO and the difficulty of substituting Lu and Si sites with these elements was analyzed. For 15 doping cases, the defect formation energies are directly calculated and compared with the corresponding relaxation energies. The results suggest that the relaxation energy could serve the purpose stated above. This descriptor is expected to play a more important role in larger‐scale screening for defect engineering in LSO and other inorganic nonmetallic materials, for example, when codoping is planned for.