Metallic conduction and superconductivity in the pseudogap phase

TL;DR

This paper presents a theoretical analysis of the pseudogap phase in cuprate superconductors using the t-J model, explaining metallic conduction and superconductivity through holon and spinon dynamics.

Contribution

It introduces a novel effective Hamiltonian capturing holon and spinon interactions, explaining the emergence of metallicity and superconductivity in the pseudogap phase.

Findings

Holons form a charge Fermi liquid below T*

Superconductivity arises from holon pairing and hopping

The two-sublattice structure underpins the phase transitions

Abstract

We analyze the t-J model on a square lattice using bosonic spinons and fermionic holons for low density x of holes. Spinons are paired into singlets, which condense below a temperature T*. The condensate evolves out of the Mott phase - preserving its symmetry. For T > T* holons and spinons are confined (by gauge forces), so that there is no coherent charge propagation. Metallic conduction and d-wave superconductivity result from separate, sublattice-preserving, holon hopping processes which originate below T* from a coupling with the condensate. A simple effective Hamiltonian describing these processes is derived and solved. Holons form a charge Fermi liquid, becoming incoherent (confined) above T*. In the superconductor holons hop as pairs, reducing kinetic energy. The two-sublattice property is the glue that connects the three phases; its effect can be seen in various correlation functions. The theory can account for many features of the cuprate superconductors, including the origin of two-dimensional metallicity.