# Tunneling probe of fluctuating superconductivity in disordered thin films

## TL;DR

This paper investigates how finite-range superconducting fluctuations affect the tunneling spectra in disordered thin films near the superconductor-insulator transition, explaining suppressed coherence peaks observed experimentally.

## Contribution

It provides a theoretical framework using diagrammatic resummation to quantitatively describe tunneling spectra influenced by superconducting fluctuations on the insulating side of the SIT.

## Key findings

- Short-range fluctuations suppress coherence peaks in tunneling spectra.
- The model matches experimental tunneling data in disordered thin films.
- Accounts for pseudo-gap features in high-temperature superconductors.

## Abstract

Disordered thin films close to the superconducting-insulating phase transition (SIT) hold the key to understanding quantum phase transition in strongly correlated materials. The SIT is governed by superconducting quantum fluctuations, which can be revealed for example by tunneling measurements. These experiments detect a spectral gap, accompanied by suppressed coherence peaks that do not fit the BCS prediction. To explain these observations, we consider the effect of finite-range superconducting fluctuations on the density of states, focusing on the insulating side of the SIT. We perform a controlled diagrammatic resummation and derive analytic expressions for the tunneling differential conductance. We find that short-range superconducting fluctuations suppress the coherence peaks, even in the presence of long-range correlations. Our approach offers a quantitative description of existing measurements on disordered thin films and accounts for tunneling spectra with suppressed coherence peaks observed, for example, in the pseudo gap regime of high-temperature superconductors.