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


  • The authors thank R. Detemple, D. Wamwangi, W. Welnic, X. Zhang, and S. Ziegler for helpful discussions and stimulating experiments. Financial support by the Fonds der chemischen Industrie is also acknowledged. One of the authors (M. Luo) thanks the financial support by the Pao Yu-Kong and Pao Zhao-Long scholarship for Chinese students studying abroad.


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 sp3-bonding (see Figure).