D-wave superconductivity in boson+fermion dimer models

TL;DR

This study uses a slave-particle mean-field approach to analyze a boson+fermion quantum dimer model, revealing d-wave superconductivity and specific Fermi surface features relevant to cuprate high-temperature superconductors.

Contribution

It demonstrates that the boson+fermion dimer model naturally leads to d-wave superconductivity with four fermion pockets matching hole doping levels.

Findings

Identification of four charge e fermion pockets with area equal to doping p.

Dimers are unstable to d-wave superconductivity at low temperatures.

Presence of eight Dirac cones in the superconducting dispersion.

Abstract

We present a slave-particle mean-field study of the mixed boson+fermion quantum dimer model introduced by Punk, Allais, and Sachdev [PNAS 112, 9552 (2015)] to describe the physics of the pseudogap phase in cuprate superconductors. Our analysis naturally leads to four charge e fermion pockets whose total area is equal to the hole doping p, for a range of parameters consistent with the t-J model for high temperature superconductivity. Here we find that the dimers are unstable to d-wave superconductivity at low temperatures. The region of the phase diagram with d-wave rather than s-wave superconductivity matches well with the appearance of the four fermion pockets. In the superconducting regime, the dispersion contains eight Dirac cones along the diagonals of the Brillouin zone.