Chemical bonding theory of single crystal growth and its application to fast single crystal growth of rare earth inorganic materials

Abstract

Fast growth of rare earth single crystals with high melting point can effectively reduce the cost of crystal growth. However, too fast growth rate will cause supercooling upon the melt interface, which will result in a series of quality problems such as cracking. In this paper, the crystal growth process is studied from the perspective of chemical bonding at the growing interface. Combining the potential variations of crystal constituents and the coupling of chemical reaction and diffusion at the growing interface, we demonstrate that both crystallization thermodynamics and kinetics coordinately control the chemical bonding process and enhance the dominant role of chemical bonding architectures at the growing interface during crystal growth. In addition, the bonding characteristics of rare earth ions are further studied in the view of the orbital hybridization, which is useful to study the chemical bonding architecture of rare earth ions at the growing interface. For large-size rare earth oxide single crystals, the optimized crystal growth parameters can be designed on the basis of chemical bonding theory of single crystal growth. These growth parameters promote the anisotropic crystal thermodynamic expression and the isotropic crystal kinetic expression that are controlled in different scales, and help to realize the fast growth of large-size rare earth single crystals with high quality.