Suppression of d-wave superconductivity in the checkerboard Hubbard model

TL;DR

This study uses quantum Monte Carlo simulations to show that introducing checkerboard inhomogeneity in the Hubbard model suppresses the d-wave superconducting transition temperature, linking it to spin excitations and pairing interactions.

Contribution

It demonstrates how inhomogeneity in hopping parameters affects superconductivity in the Hubbard model, providing insights into the suppression mechanism.

Findings

Inhomogeneity suppresses the superconducting transition temperature $T_c$.

Decreased $T_c$ correlates with lower spin excitation energy.

Diminished d-wave pairing interaction accompanies the suppression.

Abstract

Using a dynamical cluster quantum Monte Carlo approximation we investigate the d-wave superconducting transition temperature $T_c$ in the doped 2D repulsive Hubbard model with a weak inhomogeneity. The inhomogeneity is introduced in the hoppings $\tp$ and $t$ in the form of a checkerboard pattern where $t$ is the hopping within a $2\times2$ plaquette and $\tp$ is the hopping between the plaquettes. We find inhomogeneity suppresses $T_c$. The characteristic spin excitation energy and the strength of d-wave pairing interaction decrease with decreasing $T_c$ suggesting a strong correlation between these quantities.