1Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, Budapest H-1525, Hungary
2BCAST, Brunel University, Uxbridge, Middlesex, UB8 3PH, United Kingdom
3Department of Mathematical Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, U.K.
Structural aspects of crystal nucleation in undercooled liquids are explored using a nonlinear
hydrodynamic theory of freezing proposed recently, which is based on combining fluctuating
hydrodynamics with the phase-field crystal (PFC) theory. It will be shown that unlike the usual PFC
models of diffusive dynamics, within the hydrodynamic approach not only the homogeneous and
heterogeneous nucleation processes are accessible, but also growth front nucleation, which leads
to the formation of differently oriented grains at the front in highly undercooled systems. Formation
of dislocations at the solid-liquid interface and the interference of density waves ahead of the
crystallization front are responsible for the appearance of new orientations.