The potential of chemical bonding to design crystallization and vitrification kinetics

• Published in: Nature communications Vol. 12; no. 1; p. 4978
• Main Authors: Persch, Christoph, Müller, Maximilian J., Yadav, Aakash, Pries, Julian, Honné, Natalie, Kerres, Peter, Wei, Shuai, Tanaka, Hajime, Fantini, Paolo, Varesi, Enrico, Pellizzer, Fabio, Wuttig, Matthias
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17-08-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1005/1008; 639/766/119/995; Atomic properties; Calorimetry; Chemical bonds; Covalence; Crystal structure; Crystallinity; Crystallization; Design; Humanities and Social Sciences; Kinetics; Material properties; multidisciplinary; Optical properties; Phase change materials; Quantum chemistry; Science; Science (multidisciplinary); Stoichiometry; Trends; Vitrification
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-25258-3

Controlling a state of material between its crystalline and glassy phase has fostered many real-world applications. Nevertheless, design rules for crystallization and vitrification kinetics still lack predictive power. Here, we identify stoichiometry trends for these processes in phase change materials, i.e. along the GeTe-GeSe, GeTe-SnTe, and GeTe-Sb
2
Te
3
pseudo-binary lines employing a pump-probe laser setup and calorimetry. We discover a clear stoichiometry dependence of crystallization speed along a line connecting regions characterized by two fundamental bonding types, metallic and covalent bonding. Increasing covalency slows down crystallization by six orders of magnitude and promotes vitrification. The stoichiometry dependence is correlated with material properties, such as the optical properties of the crystalline phase and a bond indicator, the number of electrons shared between adjacent atoms. A quantum-chemical map explains these trends and provides a blueprint to design crystallization kinetics.
Tailoring the crystallization kinetics of materials is important for targeting applications. Here the authors observe a remarkable dependence of crystallization and vitrification kinetics and attribute it to systematic bonding changes for a class of materials between metallic and covalent bonding.