Double dispersion of the magnetic resonant mode in cuprates

TL;DR

This paper investigates the magnetic excitation spectra in cuprates, revealing a double dispersion of the resonant peak influenced by doping levels and superconducting gaps, using a memory-function approach.

Contribution

It introduces a theoretical explanation for the double dispersion phenomenon in magnetic resonant modes in cuprates, considering doping and pseudogap effects.

Findings

Double dispersion occurs at intermediate doping levels.

Anisotropy in dispersion is rotated between branches.

Similar behavior with spin-wave dispersion at low doping.

Abstract

The magnetic excitation spectra in the vicinity of the resonant peak, as observed by inelastic neutron scattering in cuprates, are studied within the memory-function approach. It is shown that at intermediate doping the superconducting gap induces a double dispersion of the peak, with an anisotropy rotated between the downward and upward branch. Similar behavior, but with a spin-wave dispersion at higher energies, is obtained for the low-doping case assuming a large pairing pseudogap.