Vortex Glass is a Metal: Unified Theory of the Magnetic Field and Disorder-Tuned Bose Metals

TL;DR

This paper presents a unified theory showing that vortex glass phases are metallic, explaining experimental observations of non-zero resistivity in vortex glasses and Bose metals, and analyzing transport properties near phase transitions.

Contribution

It introduces a theoretical framework demonstrating that vortex glass is a metal at zero temperature, unifying experimental findings on metallic behavior in disordered superconducting systems.

Findings

Magnetic field preserves metallic transport in the glassy phase.

Resistivity near the transition scales as (H-H_c)^2, matching experiments.

Metallic state persists in three dimensions and with dissipation.

Abstract

We consider the disordered quantum rotor model in the presence of a magnetic field. We analyze the transport properties in the vicinity of the multicritical point between the superconductor, phase glass and paramagnetic phases. We find that the magnetic field leaves metallic transport of bosons in the glassy phase in tact. In the vicinity of the vicinity of the superconductivity-to-Bose metal transition, the resistitivy turns on as $(H-H_c)^{2}$ with $H_c$. This functional form is in excellent agreement with the experimentally observed turn-on of the resistivity in the metallic state in MoGe, namely $R\approx R_c(H-H_c)^\mu$, $1<\mu<3$. The metallic state is also shown to presist in three spatial dimensions. In addition, we also show that the metallic state remains intact in the presence of Ohmic dissipation in spite of recent claims to the contrary. As the phase glass in $d=3$ is identical to the vortex glass, we conclude that the vortex glass is, in actuality, a metal rather than a superconductor at T=0. Our analysis unifies the recent experiments on vortex glass systems in which the linear resistivity remained non-zero below the putative vortex glass transition and the experiments on thin films in which a metallic phase has been observed to disrupt the direct transition from a superconductor to an insulator.