Two-dimensional liquid crystalline growth within a phase-field-crystal model.
By using a two-dimensional phase-field-crystal (PFC) model, the liquid crystalline growth of the plastic triangular phase is simulated with emphasis on crystal shape and topological defect formation. The equilibrium shape of a plastic triangular crystal (PTC) grown from an isotropic phase is compared with that grown from a columnar or smectic-A (CSA) phase. While the shape of a PTC nucleus in the isotropic phase is almost identical to that of the classical PFC model, the shape of a PTC nucleus in CSA is affected by the orientation of stripes in the CSA phase, and irregular hexagonal, elliptical, octagonal, and rectangular shapes are obtained. Concerning the dynamics of the growth process, we analyze the topological structure of the nematic order, which starts from nucleation of +1/2 and -1/2 disclination pairs at the PTC growth front and evolves into hexagonal cells consisting of +1 vortices surrounded by six satellite -1/2 disclinations. It is found that the orientational and the positional order do not evolve simultaneously; the orientational order evolves behind the positional order, leading to a large transition zone, which can span over several lattice spacings.
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Youyi Western Road 127, 710072 Xi'an, China.|Institut für Wissenschaftliches Rechnen, Technische Universität Dresden, 01062 Dresden, Germany.
Sai
S
Tang
Institut für Wissenschaftliches Rechnen, Technische Universität Dresden, 01062 Dresden, Germany.
Simon
S
Praetorius
Institut für Wissenschaftliches Rechnen, Technische Universität Dresden, 01062 Dresden, Germany.
Rainer
R
Backofen
Institut für Wissenschaftliches Rechnen, Technische Universität Dresden, 01062 Dresden, Germany.|Center of Advanced Modeling and Simulations, Technische Universität Dresden, 01062 Dresden, Germany.
Axel
A
Voigt
Institute of Physics, Chinese Academy of Science, P.O. Box 603, 100190 Beijing, China.
Yan-Mei
YM
Yu
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Youyi Western Road 127, 710072 Xi'an, China.
Jincheng
J
Wang