Superconductivity and the Pseudogap in the two-dimensional Hubbard model

TL;DR

This paper uses advanced numerical methods to study the Hubbard model, revealing how superconductivity emerges near the Mott insulator and pseudogap phases, mirroring behaviors seen in copper-oxide superconductors.

Contribution

It explicitly constructs the superconducting state in the Hubbard model and details its relationship with the pseudogap and Mott insulator phases, highlighting new insights into high-temperature superconductivity.

Findings

Superconductivity occurs near the Mott insulator but separated by a pseudogap phase.

The maximum transition temperature coincides with the onset of the pseudogap.

Superconductivity emergence reduces the excitation gap, consistent with experimental observations.

Abstract

Recently developed numerical methods have enabled the explicit construction of the superconducting state of the Hubbard model of strongly correlated electrons in parameter regimes where the model also exhibits a pseudogap and a Mott insulating phase. $d_{x^2-y^2}$ symmetry superconductivity is found to occur in proximity to the Mott insulator, but separated from it by a pseudogapped nonsuperconducting phase. The superconducting transition temperature and order parameter amplitude are found to be maximal at the onset of the normal-state pseudogap. The emergence of superconductivity from the normal state pseudogap leads to a decrease in the excitation gap. All of these features are consistent with the observed behavior of the copper-oxide superconductors.