Phase change materials: Chalcogenides with remarkable properties due to an unconventional bonding mechanism

Phase change materials are characterized by a unique property combination which encompasses a pronounced property contrast between the amorphous and crystalline state, as well as rapid crystallization. This property portfolio is ideally suited for data storage applications. In this paper, the understanding of the relationship between the properties of phase change materials and their mechanism of chemical bonding will be reviewed in an attempt to provide a generic explanation for many of the unconventional properties of phase change materials.