Theory of dual fermion superconductivity in hole-doped cuprates

TL;DR

This paper presents a dual fermion model explaining the phase diagram of hole-doped cuprates, including strange metal behavior, pseudogap formation, and d-wave superconductivity, emphasizing high-energy spin fluctuations as the pairing mechanism.

Contribution

It introduces a dual fermion theoretical framework that accounts for the complex phases of hole-doped cuprates, highlighting the role of high-energy spin excitations in superconductivity.

Findings

Strange metal behavior arises from carriers in copper antiferromagnetic spin fluctuations.

High-energy spin excitations act as the 'magnetic glue' for d-wave pairing.

The pseudogap results from carrier localization or a crossover to a Kondo-like insulator.

Abstract

Since the discovery of the cuprate high-temperature superconductivity in 1986, a universal phase diagram has been constructed experimentally and numerous theoretical models have been proposed. However, there remains no consensus on the underlying physics thus far. Here, we theoretically investigate the phase diagram of hole-doped cuprates based on an itinerant-localized dual fermion model, with the charge carriers doped on the oxygen sites and localized holes on the copper $d_{x^{2}-y^{2}}$ orbitals. We analytically demonstrate that the puzzling anomalous normal state or the strange metal could simply stem from a free Fermi gas of carriers bathing in copper antiferromagnetic spin fluctuations. The short-range high-energy spin excitations also act as the `magnetic glue' of carrier Cooper pairs and induce $d$-wave superconductivity from the underdoped to overdoped regime, distinctly diffrent from the conventional low-frequency magnetic fluctuation mechanism. We further sketch out the characteristic dome-shaped critical temperature $T_c$ versus doping level. The emergence of the pseudogap is ascribed to the localization of partial carriers coupled to the local copper moments or a crossover from the strange metal to a nodal Kondo-like insulator. Our work provides a consistent theoretical framework to understand the typical phase diagram of hole-doped cuprates and paves a distinct way to the studies of both non-Fermi liquid and unconventional superconductivity in strongly correlated systems.