Crystal structures and freezing of dipolar fluids

Abstract

We investigate the crystal structure of classical systems of spherical particles with an embedded point dipole at T=0. The ferroelectric ground state energy is calculated using generalizations of the Ewald summation technique. Due to the reduced symmetry compared to the nonpolar case the crystals are never strictly cubic. For the Stockmayer (i.e., Lennard-Jones plus dipolar) interaction three phases are found upon increasing the dipole moment: hexagonal, body-centered orthorhombic, and body-centered tetragonal. An even richer phase diagram arises for dipolar soft spheres with a purely repulsive inverse power law potential $\sim r^{-n}$. A crossover between qualitatively different sequences of phases occurs near the exponent $n=12$. The results are applicable to electro- and magnetorheological fluids. In addition to the exact ground state analysis we study freezing of the Stockmayer fluid by density-functional theory.

submitted to Phys. Rev. E

References in corpus (3)

• Structure of Electrorheological Fluids
• Ordering of dipolar Ising crystals
• Inhomogeneous magnetization in dipolar ferromagnetic liquids

Cited by in corpus (12)

• Magnetic properties of colloidal suspensions of interacting magnetic particles
• Stable crystalline lattices in two-dimensional binary mixtures of dipolar particles
• Structure and melting behavior of classical bilayer crystals of dipoles
• Ground state of dipolar hard spheres confined in channels
• The ferromagnetic transition and domain structure in LiHoF4
• Phase transitions and ordering of confined dipolar fluids
• Model Energy Landscapes of Low-Temperature Fluids: Dipolar Hard Spheres
• Local orientational order in the Stockmayer liquid
• Classical crystal formation of dipoles in two dimensions
• Ferroelectric glass of spheroidal dipoles with impurities: Polar nanoregions, response to applied electric field, and ergodicity breakdown
• Paraelectric and ferroelectric order in two-state dipolar fluids
• New solid phase of dipolar systems