Free energy functionals for efficient phase field crystal modeling of structural phase transformations

TL;DR

This paper develops a new class of free energy functionals for the phase field crystal method, enabling the modeling of various crystalline structures and phase transformations with improved accuracy and control over physical parameters.

Contribution

It introduces a systematic construction of two-particle correlation functions that extend PFC modeling to a broader range of lattice symmetries and structures.

Findings

Enables modeling of diverse crystalline structures beyond triangular and BCC.

Provides control over temperature and surface energy anisotropy.

Demonstrates effectiveness through two structural phase transformation examples.

Abstract

The phase field crystal (PFC) method has emerged as a promising technique for modeling materials with atomistic resolution on mesoscopic time scales. The approach is numerically much more efficient than classical density functional theory (CDFT), but its single mode free energy functional only leads to lattices with triangular (2D) or BCC (3D) symmetries. By returning to a closer approximation of the CDFT free energy functional, we develop a systematic construction of two-particle direct correlation functions that allow the study of a broad class of crystalline structures. This construction examines planar spacings, lattice symmetries, planar atomic densities and the atomic vibrational amplitude in the unit cell of the lattice and also provides control parameters for temperature and anisotropic surface energies. The power of this new approach is demonstrated by two examples of structural phase transformations.