Orbital-selective electronic excitation in phase-change memory materials: a brief review

Ultrafast laser-induced phase/structural transitions show a great potential in optical memory and optical computing technologies, which are believed to have advantages of ultrafast speed, low power consumption, less heat diffusion and remote control as compared with electronic devices. Here, we review and discuss the principles of orbital-selective electronic excitation and its roles in phase/structural transitions of phase-change memory (PCM) materials, including Sc0.2Sb1.8Te3 and GeTe phases. It is demonstrated, that the mechanism can influence the dynamics or results of structural transitions, such as an ultrafast amorphization of Sc0.2Sb1.8Te3 and a non-volatile order-to-order structural transition of GeTe. Without thermal melting, these structural transitions have the advantages of ultrafast speed and low power consumption. It suggests that the orbital-selective electronic excitation can play a significant role in discovering new physics of phase change and shows a potential for new applications.