Properties of the Bose glass phase in irradiated superconductors near the matching field

TL;DR

This study uses Monte Carlo simulations to explore the properties of the Bose glass phase in irradiated superconductors near the matching field, revealing how disorder and interaction range influence the presence of Mott insulator features.

Contribution

It demonstrates how vortex interactions and defect distributions affect the stability of the Mott insulator phase in the Bose glass, providing insights for experimental observation.

Findings

Random defect distribution destroys the Mott insulator phase at B = B_Phi.

Remnants of Mott insulator singularities persist for lambda/d <= 1.

Regular defect arrangements can sustain the Mott insulator phase at larger interaction ranges.

Abstract

Structural and transport properties of interacting localized flux lines in the Bose glass phase of irradiated superconductors are studied by means of Monte Carlo simulations near the matching field B_Phi, where the densities of vortices and columnar defects are equal. For a completely random columnar pin distribution in the xy-plane transverse to the magnetic field, our results show that the repulsive vortex interactions destroy the Mott insulator phase which was predicted to occur at B = B_Phi. On the other hand, for ratios of the penetration depth to average defect distance lambda/d <= 1, characteristic remnants of the Mott insulator singularities remain visible in experimentally accessible quantities as the magnetization, the bulk modulus, and the magnetization relaxation, when B is varied near B_Phi. For spatially more regular disorder, e.g., a nearly triangular defect distribution, we find that the Mott insulator phase can survive up to considerably large interaction range \lambda/d, and may thus be observable in experiments.