Correlations of two-dimensional super-paramagnetic colloids in tilted external magnetic fields

Waves in a quasi-two-dimensional superparamagnetic dusty plasma liquid in a trap

In a two-dimensional (2D) dusty plasma composed of superparamagnetic, charged dust grains and immersed in an external magnetic field B, the grains interact via both Yukawa and magnetic dipole-dipole potentials. Because the grains' magnetic dipole moments are induced by B, the dipole moments all lie along B. When B is tilted with respect to the normal to the dust layer, the interaction between the grains becomes anisotropic. In our previous paper [Hartmann et al., Phys. Rev. E 89, 043102 (2014)PLEEE81539-375510.1103/PhysRevE.89.043102], we studied the character of waves in such a system, confined strictly to two dimensions, without any spatial extension in the direction perpendicular to the layer. We analyzed how the dispersion of waves depends on the direction of propagation and the relative strengths of the magnetic dipole and Yukawa potentials. In this paper, we consider a more realistic quasi-2D system where the grains are confined by an external potential and can undergo small oscillations perpendicular to the layer. We analyze the effect of the strength of the confining potential on the in-plane correlations and on the wave propagation. In addition to the in-plane compressional and transverse waves, there now appears an out-of-plane transverse wave generated by the oscillation of the grains in the confining potential. The theoretical approach uses the quasi-localized charge approximation paralleled by molecular dynamics simulations.

Waves in two-dimensional superparamagnetic dusty plasma liquids

Wave dispersion relations in the strongly coupled liquid phase of a two-dimensional system of dust grains interacting via both Yukawa and dipole interactions are investigated. The model system comprises a layer of charged superparamagnetic grains in a plasma in an external, uniform magnetic field B whose magnitude and direction can be varied. Because the induced magnetic dipole moments of the grains lie along B, the interaction between the grains becomes anisotropic as B is tilted with respect to the layer. The theoretical approach uses a reformulated quasilocalized charge approximation that can treat dipole interactions, combined with molecular dynamics simulations. The mode dispersion relations are found to depend on the relative strengths of the Yukawa and dipole interactions and the direction of wave propagation in the plane.

Association of limited valence patchy particles in two dimensions

We investigate theoretically the phase behavior of particles with limited valence in two dimensions, by solving the first-order Wertheim theory form. As previously found for three dimensions, in two dimensions also the valence has a strong impact on the phase diagram, controlling the location of the gas-liquid coexistence. On decreasing the valence, the critical density and temperature decrease while the region of gas-liquid instability shrinks and vanishes. At low temperatures, the system reaches its ground state with particles forming a fully bonded network which spans the system.