Gossamer Superconductor, Mott Insulator, and Resonating Valence Bond State in Correlated Electron Systems

TL;DR

This paper uses the Gutzwiller variational method to study a 2D Hubbard model, revealing a transition from gossamer superconductivity to Mott insulator as Coulomb repulsion increases, highlighting connections to RVB states.

Contribution

It demonstrates the existence of gossamer superconductivity in a Hubbard model and characterizes its properties relative to Mott insulators and RVB states.

Findings

Gossamer superconductor occurs at low Coulomb repulsion U.

Mott insulator appears at high U.

Chemical potential is pinned near the middle of Hubbard bands.

Abstract

Gutzwiller variational method is applied to an effective two-dimensional Hubbard model to examine the recently proposed gossamer superconductor by Laughlin. The ground state at half filled electron density is a gossamer superconductor for smaller intra-site Coulomb repulsion U and a Mott insulator for larger U. The gossamer superconducting state is similar to the resonant valence bond superconducting state, except that the chemical potential is approximately pinned at the mid of the two Hubbard bands away from the half filled.