Theory of pseudogap and superconductivity in doped Mott insulators

TL;DR

This paper presents a theoretical framework explaining the pseudogap and superconductivity in doped Mott insulators through the evolution of Green's function zeros and poles, introducing cofermions as key players.

Contribution

It introduces the cofermion concept within the slave-boson framework to explain pseudogap formation and pairing mechanisms in underdoped cuprates.

Findings

Reproduces pseudogap and Fermi arc structures using cluster dynamical mean-field theory.

Identifies topological transitions involving zeros and poles in Green's function.

Proposes cofermions as a unifying element for Mottness and superconductivity.

Abstract

Underdoped Mott insulators provide us with a challenge of many-body physics. Recent renewed understanding is discussed in terms of the evolution of pole and zero structure of the single-particle Green's function. Pseudogap as well as Fermi arc/pocket structure in the underdoped cuprates is well reproduced from the recent cluster extension of the dynamical mean-field theory. Emergent coexisting zeros and poles set the underdoped Mott insulator apart from the Fermi liquid, separated by topological transitions. Cofermion proposed as a generalization of exciton in the slave-boson framework accounts for the origin of the zero surface formation. The cofermion-quasiparticle hybridization gap offers a natural understanding of the pseudogap and various unusual Mottness. Furthermore the cofermion offers a novel pairing mechanism, where the cofermion has two roles: It reinforces the Cooper pair as a pair partner of the quasiparticle and acts as a glue as well. It provides a strong insight for solving the puzzle found in the dichotomy of the gap structure.