Composite-Fermion Theory for Pseudogap, Fermi Arc, Hole Pocket, and Non-Fermi-Liquid of Underdoped Cuprate Superconductors

TL;DR

This paper introduces a theoretical extension of exciton concepts to doped Mott insulators, explaining pseudogap phenomena, Fermi arcs, and non-Fermi-liquid behavior in underdoped cuprate superconductors through cofermion hybridization.

Contribution

It proposes a novel fermionic excitation called cofermions and their hybridization with quasiparticles to explain key features of underdoped cuprates.

Findings

Pseudogap arises from hybridization gap due to cofermions.

Fermi surface reconstruction explains Fermi arcs and pockets.

The theory accounts for non-Fermi-liquid behavior in underdoped cuprates.

Abstract

We propose that an extension of the exciton concept to doped Mott insulators offers a fruitful insight into challenging issues of the copper oxide superconductors. In our extension, new fermionic excitations called cofermions emerge in conjunction to generalized excitons. The cofermions hybridize with conventional quasiparticles. Then a hybridization gap opens, and is identified as the pseudogap observed in the underdoped cuprates. The resultant Fermi-surface reconstruction naturally explains a number of unusual properties of the underdoped cuprates, such as the Fermi arc and/or pocket formation.