Wigner crystals for a planar, equimolar binary mixture of classical, charged particles

Abstract

We have investigated the ground state configurations of an equimolar, binary mixture of classical charged particles (with nominal charges Q1 and Q2) that condensate on a neutralizing plane. Using efficient Ewald summation techniques for the calculation of the ground state energies, we have identified the energetically most favorable ordered particle arrangements with the help of a highly reliable optimization tool based on ideas of evolutionary algorithms. Over a large range of charge ratios, q=Q2/ Q1, we identify six non-trivial ground states, some of which show a remarkable and unexpected structural complexity. For 0.59 lesssim q < 1 the system undergoes a phase separation where the two charge species populate in a hexagonal arrangement spatially separated areas.

Keywords

• Wigner crystals
• binary mixture of charged systems
• ground states
• Ewald summation
• evolutionary algorithm