Theory for Gossamer and Resonating Valence Bond Superconductivity

TL;DR

This paper develops a theoretical framework for understanding gossamer and resonating valence bond superconductivity in the two-dimensional Hubbard model, highlighting phase transitions and the role of strong correlations.

Contribution

It introduces a renormalized mean field theory incorporating strong correlations via Gutzwiller wavefunctions for the Hubbard model.

Findings

First order phase transition from Mott insulator to gossamer superconductor at half filling.

Evolution of Mott insulator into resonating valence bond state away from half filling.

Adiabatic connection between RVB state and gossamer superconductor.

Abstract

We use an effective Hamiltonian for two-dimensional Hubbard model including an antiferromagnetic spin-spin coupling term to study recently proposed gossamer superconductivity. We formulate a renormalized mean field theory to approximately take into account the strong correlation effect in the partially projected Gutzwiller wavefucntions. At the half filled, there is a first order phase transition to separate a Mott insulator at large Coulomb repulsion U from a gossamer superconductor at small U. Away from the half filled,the Mott insulator is evolved into an resonating valence bond state, which is adiabatically connected to the gossamer superconductor.