6 research outputs found
Binary crystals in two-dimensional two-component Yukawa mixtures
The zero-temperature phase diagram of binary mixtures of particles
interacting via a screened Coulomb pair potential is calculated as a function
of composition and charge ratio. The potential energy obtained by a Lekner
summation is minimized among a variety of candidate two-dimensional crystals. A
wealth of different stable crystal structures is identified including
structures [ particles correspond to large
(small) charge.] Their elementary cells consist of triangular, square or
rhombic lattices of the particles with a basis comprising various
structures of and particles. For small charge asymmetry there are no
intermediate crystals besides the pure and triangular crystals.Comment: RevTeX 4 - 17 pages - 6 main figure
Ultra-fast quenching of binary colloidal suspensions in an external magnetic field
An ultra-fast quench is applied to binary mixtures of superparamagnetic
colloidal particles confined at a two-dimensional water-air interface by a
sudden increase of an external magnetic field. This quench realizes a virtually
instantaneous cooling which is impossible in molecular systems. Using
real-space experiments, the relaxation behavior after the quench is explored.
Local crystallites with triangular and square symmetry are formed on different
time scales and the correlation peak amplitude of the small particles evolves
nonmonotonically in time in agreement with Brownian dynamics computer
simulations.Comment: 4 pages, 4 figure