Spectral Properties of Magnetic Excitations in Cuprate Two-Leg Ladder Systems

TL;DR

This paper reviews and extends the microscopic understanding of magnetic excitations in cuprate two-leg ladder systems, highlighting spectral properties and recent experimental correlations.

Contribution

It provides a comprehensive overview of the magnetic excitation spectrum in cuprate ladders, including energies, spectral weights, and the effects of additional four-spin interactions.

Findings

Almost complete understanding of magnetic excitations in undoped cuprate ladders.

Spectral properties match experimental observations from neutron, Raman, and infrared scattering.

Four-spin interactions are significantly smaller than Heisenberg exchange terms.

Abstract

This article summarizes and extends the recent developments in the microscopic modeling of the magnetic excitations in cuprate two-leg ladder systems. The microscopic Hamiltonian comprises dominant Heisenberg exchange terms plus an additional four-spin interaction which is about five times smaller. We give an overview over the relevant energies like the one-triplon dispersion, the energies of two-triplon bound states and the positions of multi-triplon continua and over relevant spectral properties like spectral weights and spectral densities in the parameter regime appropriate for cuprate systems. It is concluded that an almost complete understanding of the magnetic excitations in undoped cuprate ladders has been obtained as measured by inelastic neutron scattering, inelastic light (Raman) scattering and infrared absorption.