bcc symmetry in the crystal-melt interface of Lennard-Jones fluids examined through density functional theory

Using a density functional theory for Lennard-Jones fluids, we find significant bcc (body-centered-cubic) character in both the planar interface between the stable fee (face-centered-cubic) crystal and the stable liquid and at the interface of the critical fee nucleus in a metastable liquid. We introduce an order parameter that continuously distorts a crystal with fee symmetry to one with bcc symmetry. Our results suggest that metastable phases may have large effects on equilibrium interfaces and on rates of first-order phase transitions.