Orientation-strain glass formation in anisotropic particle systems with impurities

Abstract

We propose a modified Lennard-Jones potential to simulate phase transitions in crystals composed of elliptic particles, and orientation-strain glass formation with addition of isotropic impurities in two dimensions. In one-component anisotropic systems, we find an order-disorder phase transition of orientational degree of freedom in crystals, which is also a structural phase transition because particle anisotropy induces lattice deformation. With increasing the concentration of the impurities, orientationally ordered domains are finely divided, yielding orientation-strain glass with mesoscopically ordered regions still surviving. Planar anchoring of elliptic particles occurs around impurity surfaces. Temperature dependence of orientational order and rotational dynamics of molecular orientations are discussed. We also predict a shape memory effect under a stretching cycle due to inter-variant transformation. © 2013 American Institute of Physics.