Vortex stripe glass with self-generated randomness

TL;DR

This paper demonstrates a finite temperature vortex glass transition in frustrated Josephson junction arrays without quenched disorder, revealing anisotropic vortex structures and direction-dependent flow properties akin to jamming phenomena.

Contribution

It uncovers a novel vortex glass transition driven by self-generated randomness in anisotropic JJAs, linking it to Aubry's transition and anisotropic vortex dynamics.

Findings

Vortexes form zigzag stripes along weaker coupling directions.

The vortex solid can flow smoothly in the stronger coupling direction.

The system exhibits direction-dependent jamming and flow behavior.

Abstract

We found a finite temperature glass transition in the absence of quenched disorder in frustrated Josephson junction arrays (JJA) on a square lattice with anisotropic Josephson couplings by numerical simulations. The vortexes develop zigzag stripes into the direction of weaker coupling at low temperatures. The whole amorphous vortex solid can flow smoothly into the direction of stronger coupling by non-trivial soft modes. As the result the macroscopic phase coherence is destroyed being reminiscent of vortex flow in pure bulk superconductors or spin-chirality decoupling in frustrated magnets. On the contrary such soft-modes are absent into the direction of weaker coupling. Consequently the system behaves as a Ohmic (unjammed) liquid or superconducting (jammed) solid with respect to injection of external electric current, i. e. shear, along different directions. This jamming-glass transition can be regarded as a two dimensional realization of the Aubry's transition.