About one unified description of the first- and second-order phase transitions in the phase-field crystal model

Modeling of crystal micro-structures and their dynamics during fast phase transitions can be performed by the phase-field crystal (PFC) model in the hyperbolic formulation (Modified Phase Field Crystal [MPFC] model). This method is suitable for a continual modeling of the atomic density field at diffusion time intervals (slow diffusion dynamics) and short intervals of atomic flux relaxation (fast structural relaxation). Since the PFC model describes transitions of the first and second order, we present a description of both transitions in a unified manner. We show how phase transitions of each order can be treated using specific analytical transformations. To justify the unified approach to description of the first- and second-order transformations, we provide results of numerical simulation of phase changes between homogeneous structure and Body Centered Cubic (BCC) crystal lattice. The set of benchmarks for different domains shows coincidence of instantaneous atomic distributions and free energies in both forms.

Automated summary

The PFC model is used for modeling crystal micro-structures and dynamics during fast phase transitions, suitable for both first and second order transitions. Specific analytical transformations are used to treat phase transitions of each order, with numerical simulation results showing consistency between atomic distributions and free energies in both forms.