Research Projects

Materials that show ultrafast phase change with contrasting property changes (phase change materials) are the key components of phase change memory (PCM). PCM technology offers to surpass the Von Neumann bottleneck via in-memory computing, and hence very useful for intensive computations and data transfer involved in artificial intelligence applications. A new type of bonding called “metavalent bonding” is introduced to describe the bonding in phase-change materials. Metavalent materials are incipient metals with a bonding type that is in between covalent and metallic. They feature delocalized bonding and bond order, close to 0.5. They feature unusually large Born effective charge, optical dielectric constant and high probability of multiple events during laser assisted field evaporation, in addition to the phase change property. While metavalent bonding is often considered as a new bonding mechanism, we believe that a unique combination of electronic structural features is behind the unusual properties of phase change materials rather than a new bonding scheme, and it is our goal to find out this combination and unravel how this trigger ultrafast the phase change in such materials. This knowledge will enable us to predict better materials, and to translate our research to industrial applications and we do believe that the findings will greatly benefit the phase change memory technology.