Fluctuation Conductivity in Insulator-Superconductor Transitions with Dissipation

TL;DR

This paper investigates fluctuation conductivity near the insulator-superconductor transition in a 2D Josephson junction array with dissipation, revealing a logarithmic temperature dependence and resistivity leveling-off at intermediate temperatures, but vanishing at zero temperature.

Contribution

It provides a detailed analysis of fluctuation conductivity incorporating dissipation effects, highlighting the temperature-dependent behavior near the critical point.

Findings

Conductivity shows a logarithmic dependence on temperature ratio at the Gaussian level.

Resistivity levels off at low to intermediate temperatures due to fluctuations.

Resistivity vanishes at zero temperature, indicating a transition to superconductivity.

Abstract

We analyze here the fluctuation conductivity in the vicinity of the critical point in a 2D Josephson junction array shunted by an Ohmic resistor.We find that at the Gaussian level, the conductivity acquires a logarithmic dependence on $T/(T-T_c)$ when the dissipation is sufficiently small. In the renormalized classical regime, this logarithmic dependence gives rise to a leveling-off of the resistivity at low to intermediate temperatures when fluctuations are included. We show, however, that this trend does not persist to T=0 at which point the resistivity vanishes. The possible relationship of the leveling of the resistivity to the low temperature transport in granlar superconductors is discussed.