Phase and vacancy behaviour of hard "slanted" cubes
arXiv:1708.06212 · doi:10.1063/1.5001483
Abstract
We use computer simulations to study the phase behaviour for hard, right rhombic prisms as a function of the angle of their rhombic face (the "slant" angle). More specifically, using a combination of event-driven molecular dynamics simulations, Monte Carlo simulations, and free-energy calculations, we determine and characterize the equilibrium phases formed by these particles for various slant angles and densities. Surprisingly, we find that the equilibrium crystal structure for a large range of slant angles and densities is the simple cubic crystal - despite the fact that the particles do not have cubic symmetry. Moreover, we find that the equilibrium vacancy concentration in this simple cubic phase is extremely high and depends only on the packing fraction, and not the particle shape. At higher densities, a rhombic crystal appears as the equilibrium phase. We summarize the phase behaviour of this system by drawing a phase diagram in the slant angle - packing fraction plane.
arXiv comment8 pages, 8 figures, to be published in Journal of Chemical Physics
References in corpus (11)
- Multicanonical Ensemble: A New Approach to Simulate First-order Phase Transitions
- Predicting crystal structures: the Parrinello-Rahman method revisited
- Disordered, Quasicrystalline and Crystalline Phases of Densely Packed Tetrahedra
- Determination of phase diagrams via computer simulation: Methodology and applications to water, electrolytes and proteins
- Free energies of crystalline solids: a lattice-switch Monte Carlo method
- Phase diagram of colloidal hard superballs: from cubes via spheres to octahedra
- Vacancy-stabilized crystalline order in hard cubes
- Entropy-driven formation of prolate and oblate cholesteric phases by computer simulations
- Digital Alchemy for Materials Design: Colloids and Beyond
- Random and ordered phases of off-lattice rhombus tiles
- Frustration of the isotropic-columnar phase transition of colloidal hard platelets by a transient cubatic phase