Topological Order in an Antiferromagnetic Tetratic Phase

We study lattice melting in two-dimensional systems of spinful particles that interact antiferromagneti-cally. We argue that, for strong spin interactions, single lattice dislocations are forbidden by magnetic frustration. This leads to a melting scenario in which a tetratic phase, containing free dislocation pairs and bound disclinations, separates the solid from the liquid. We demonstrate this phase numerically in a system of hard spheres confined between parallel plates, where spins are represented by the heights of the spheres. In the tetratic phase, the spins are shown to be as antiferromagnetically ordered as allowed by their spatial configuration.

Automated summary

The study demonstrates that in systems of spinful particles with strong spin interactions, lattice melting leads to a tetratic phase separating solid from liquid, containing free dislocation pairs and bound disclinations. The spins in the tetratic phase are shown to be antiferromagnetically ordered as allowed by their spatial configuration.