Identifying optimal dopants for Sb₂Te₃ phase-change material by high-throughput ab initio calculations with experiments

Doping is used to improve the overall performance of rhombohedral Sb₂Te₃ for the application in phase-change memory (PCM). However, it is difficult and laborious to obtain the optimal dopants using the time-consuming trial and error way. By high-throughput ab initio calculations with experiments, the present work identified Scandium, Yttrium and Mercury as the optimal dopants for Sb₂Te₃ to reduce the power consumption of Sb₂Te₃-based PCM. Using Sc as an example the doping effect on the structure and property of Sb₂Te₃ has been extensively investigated. The band gap of Sb₂Te₃ linearly increases with increasing the Sc concentration by ab initio calculations, and our experimental results confirm the theoretical findings. Furthermore, based on the semi-classical Boltzmann transport theory, Sc can significantly decrease the electrical conductivity and thermal conductivity of Sb₂Te₃, and therefore reduced energy consumption of Sb₂Te₃-based PCM is expected. Finally, the ab initio molecular dynamics simulations demonstrate that Scandium can significantly improve the thermal stability of amorphous Sc-doped Sb₂Te₃, and hence the enhanced data reliability of Sb₂Te₃-based PCM. The present work provides fundamentals for fast screening optimal dopants to enhance the overall performance of Sb₂Te₃ for PCM, and the present method can be extended to other semiconductor materials.