The Dependence of Crystal Structure of Te‐Based Phase‐Change Materials on the Number of Valence Electrons

A simple criterion to identify potential phase‐change materials is developed using density functional theory. These compounds rely on the switching between an amorphous and a crystalline state. Here it is demonstrated that suitable alloys have an average valence electron number larger than 4.1 and show p‐electron bonding leading to a six‐fold coordination, while materials with a smaller number of valence electrons favor sp 3 ‐bonding (see Figure).