Dr. Shuai Wei erhält RWTH Start-Up Förderung

Dr. Shuai Wei erhält RWTH Start-Up Förderung. Thema: " The breakdown of the Stokes-Einstein relation above the melting temperature in liquid phase-change materials "

Phase-change materials (PCMs) are at the cutting edge of material research for computer memory technology. The concept of using the ultrafast switching between the amorphous and crystalline states in PCMs and their resulting strong electrical contrast for data storage has been long pursued by researchers. The better physical understanding has led to successful technology innovations such as the recently released Intel OPTANE Memory based on PCMs that accelerates computer response four times faster. Clearly, reaching the full potential for developing future memory that operates significantly faster needs a deeper insight in the phase switching behavior. The current understanding of PCMs is centered around features of their crystalline states. My recent paper pointed out that the liquid-state behavior is non-trivial and there is an urgent need to gain a deep insight in the liquid-state behavior and its connection to the unique features of crystalline states. Here, I propose an experimental study to probe the microscopic dynamics in the liquid state of PCMs using quasi-elastic neutron scattering on time-of-flight spectroscopy, which allows for direct determination of the structural relaxation time and the self-diffusion coefficient D. The validity of the Stokes-Einstein relation in PCMs will be investigated. The results will shed light on the origin of ultrafast crystallization kinetics, which in turn is essential for improving the performance of PCMs.