Preformed Pairs, SU(2) Slave-boson Theory, and High T_c Superconductors

TL;DR

This paper explores a preformed-pair model and its relation to SU(2) slave-boson theory, revealing insights into the quantum disordered phase of high T_c superconductors, including properties like Mott insulator behavior and spin gaps.

Contribution

It establishes a connection between the preformed-pair model and SU(2) slave-boson theory, providing a low energy effective theory for the quantum disordered phase.

Findings

Quantum disordered phase exhibits Mott insulator properties at zero doping.

Low doping shows spin gap and reduced superfluid density.

Effective theories are qualitatively equivalent in describing low energy physics.

Abstract

A preformed-pair model was considered. The quantum disordered phase of the d-wave superconducting state was obtained by turning on an on-site repulsion. The low energy effective theory of the quantum disordered phase was derived, which was found to be qualitatively equivalent to the low energy effective theory of the SU(2) slave-boson theory in the staggered-flux phase. Many physical properties of the disordered phase at low energies were obtained, such as the Mott insulator property at zero doping, spin gap and low superfluid density at low doping.