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

Abstract

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.