Checkerboard density of states in strong-coupling superconductors

TL;DR

This paper solves the Bogoliubov-de Gennes equations in the strong-coupling limit, revealing checkerboard modulations in the density of states due to preformed pairs with finite momentum, akin to cuprate tunneling data.

Contribution

It introduces a real-space strong-coupling approach showing checkerboard DOS modulations from preformed pairs with finite momentum.

Findings

Identification of two energy scales: incoherent gap $_p$ and coherent gap $_c(T)$.

Checkerboard modulations in the density of states similar to cuprate tunneling experiments.

Demonstration of real-space modulations in the strong-coupling superconducting regime.

Abstract

The Bogoliubov-de Gennes (BdG) equations are solved in the strong-coupling limit, where real-space (preformed) pairs bose-condense with finite center-of-mass momenta. There are two energy scales in this regime, a temperature independent incoherent gap $\Delta_p$ and a temperature dependent coherent gap $\Delta_c (T)$, modulated in real space. The single-particle density of states (DOS) reveals checkerboard modulations similar to the tunnelling DOS in cuprates.