Theory of two-particle excitations and the magnetic susceptibility in high-Tc cuprate superconductors

TL;DR

This paper develops a parameter-free theoretical approach extending the Variational Cluster Approach to two-particle excitations, successfully modeling magnetic excitations in high-Tc cuprate superconductors and matching experimental observations.

Contribution

It introduces a novel extension of the Variational Cluster Approach to two-particle excitations, providing a unified theoretical framework for magnetic excitations in HTSC.

Findings

Reproduces magnetic excitation spectra in HTSC

Captures resonance mode and hour-glass dispersion

Aligns well with experimental data

Abstract

Two-particle (2-p) excitations such as spin and charge excitations play a key role in high-Tc cuprate superconductors (HTSC). On the basis of a parameter-free theory, which extends the Variational Cluster Approach (a recently developed embedded cluster method) to 2-p excitations, the magnetic excitations of HTSC are shown to be reproduced for a Hubbard model within the relevant strong-coupling regime. In particular, the resonance mode in the underdoped regime, its intensity and "hour-glass" dispersion are in good overall agreement with experiments.