Microscopic Complexity in Phase‐Change Materials and its Role for Applications

Abstract

Phase‐change materials (PCMs) are widely used for data storage and in other functional devices. Despite their seemingly simple compositions, these materials exhibit intriguing microscopic complexity and a portfolio of interesting properties. In this Feature Article, it is shown that structural and electronic peculiarities on the atomic scale are key determinants for the technological success of PCMs. Particular emphasis is put on the interplay of different experimental and theoretical methods, on the bonding nature of crystalline and amorphous PCMs, and on the role of surfaces and nanostructures. Then, unconventional transport properties of the crystalline phases are highlighted, both with regard to electrical and heat conduction. Finally, perspectives and future directions are drawn: for finding new PCMs based on microscopic understanding, and also for new applications of these materials in emerging fields.