Microscopic Inhomogeneity and Superconducting Properties of a Two-dimensional Hubbard Model for High-$T_c$ Cuprate

TL;DR

This study uses cellular dynamical mean-field theory to explore how microscopic inhomogeneity in a two-dimensional Hubbard model affects superconducting properties, revealing spatial variations consistent with experimental observations in cuprates.

Contribution

It demonstrates that spatial electron density modulation leads to significant local variations in superconducting gap and order parameter, advancing understanding of inhomogeneity effects in high-$T_c$ superconductors.

Findings

Superconducting gap varies spatially with electron density in the model.

Hole-rich regions show enhanced superconducting order parameter.

Inhomogeneity reproduces experimental gap variations in cuprates.

Abstract

Recent scanning tunneling microscopy measurements on cuprate superconductors have revealed remarkable spatial inhomogeneities in the single-particle energy gap. Using cellular dynamical mean-field theory, we study the zero temperature superconducting properties of a single-band Hubbard model with a spatial modulation of the electron density. We find that the inhomogeneity in the electronic structure results in a substantial spatial variation in the superconducting order parameter and single-particle energy gap, reminiscent of the experimental results. In particular, we find that the order parameter and gap amplitudes in the hole-rich regions are significantly enhanced over the corresponding quantities in a uniform system, if the hole-rich regions are embedded in regions with smaller hole density.