Binary crystals in two-dimensional two-component Yukawa mixtures

TL;DR

This paper maps the zero-temperature phase diagram of two-dimensional binary Yukawa mixtures, revealing various stable crystal structures depending on composition and charge ratio, with no intermediate crystals at small charge asymmetry.

Contribution

It provides a comprehensive calculation of the phase diagram and identifies new stable binary crystal structures in two-dimensional Yukawa mixtures.

Findings

Multiple stable crystal structures identified including $A,B,AB_2, A_2B, AB_4$.

Elementary cells include triangular, square, or rhombic lattices.

No intermediate crystals for small charge asymmetry.

Abstract

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 $A,B,AB_2, A_2B, AB_4$ structures [$A$ $(B)$ particles correspond to large (small) charge.] Their elementary cells consist of triangular, square or rhombic lattices of the $A$ particles with a basis comprising various structures of $A$ and $B$ particles. For small charge asymmetry there are no intermediate crystals besides the pure $A$ and $B$ triangular crystals.