Supersolid phase in fully frustrated Josephson junction arrays

TL;DR

This paper investigates the phase diagram and excitation spectra of fully frustrated Josephson junction arrays, revealing an expanded supersolid region with two distinct phases, including a novel non-chiral supersolid phase.

Contribution

It introduces the non-chiral supersolid phase at full frustration, expanding understanding of supersolid states in Josephson junction arrays.

Findings

Supersolid region is larger at f=1/2 than at f=0.

Identifies two supersolid phases: chiral and non-chiral.

Excitation spectra show particle-like dispersions related to defectons.

Abstract

We study the phase diagram and the excitation spectra of an array of small Josephson junctions at $f=1/2$ and arbitrary charge frustration. We find that the supersolid region in the phase diagram is larger than the correspondent region at $f=0$ and it includes two different phases.In the chiral supersolid (SS) charges and vortices are arranged in a checkerboard pattern on a $2\:\times \:2$ supercell analogously to the unfrustrated case. We find a new phase, which we term {\em non-chiral supersolid} (NCSS), which has no corresponding phase at $f=0$. The excitation spectra in the supersolid regions show particle like dispersions which is related to the defectons. The defecton condensation leads to superfluidity in the presence of charge ordered background.