Viscosity anomaly and transient immiscibility in liquid Ga2Te3 promising for high-temperature memory applications

Emerging brain-inspired computing needs phase-change materials (PCMs) of the next generation with lower energy consumption and wider temperature range. Ga2Te3 has higher melting and crystallization temperatures compared to flagship PCMs and simultaneously a low switching power and fast switching rate. Fast transformation rate in PCMs at nanosecond scale is directly related to a low viscosity in the liquid state. Ga2Te3 melt shows a highly unusual anomaly, a sudden viscosity increase just above the melting point. Our preliminary HE-XRD data suggest transient liquid-liquid immiscibility is the origin of this anomaly. A detailed response can be obtained using NIMROD experiment over a wide Q-range starting from 0.01 Å-1. EPSR modeling using large simulation boxes will complete the experiment providing deep insight into atomic structure at the local and mesoscopic scale.