Tunneling spectra of layered strongly correlated d-wave superconductors

TL;DR

This paper uses a mean-field model of layered d-wave superconductors to explain diverse tunneling spectra features observed in cuprates, linking them to proximity to a Mott insulator and ARPES findings.

Contribution

It demonstrates that complex tunneling spectra features can be explained by a homogeneous layered d-wave superconductor near a Mott transition, without requiring inhomogeneity.

Findings

Reproduces bias sign asymmetry at high bias

Explains absence of Van Hove singularity in spectra

Connects spectral features to electron dispersion renormalization

Abstract

Tunneling conductance experiments on cuprate superconductors exhibit a large diversity of spectra that appear in different nano-sized regions of inhomogeneous samples. In this letter, we use a mean-field approach to the tt't''J model in order to address the features in these spectra that deviate from the BCS paradigm, namely, the bias sign asymmetry at high bias, the generic lack of evidence for the Van Hove singularity, and the occasional absence of coherence peaks. We conclude that these features can be reproduced in homogeneous layered d-wave superconductors solely due to a proximate Mott insulating transition. We also establish the connection between the above tunneling spectral features and the strong renormalization of the electron dispersion around (0,pi) and (pi,0) and the momentum space anisotropy of electronic states observed in ARPES experiments.