Raman resonance in spin S two-leg ladder systems

TL;DR

This paper predicts a pseudo-resonance peak in the Raman intensity of spin S two-leg ladder systems, linked to magnon spectrum features, with implications for understanding magnetic excitations.

Contribution

It introduces the concept of a pseudo-resonance in Raman spectra of spin ladders and relates it to magnon spectrum minima, extending the excitonic resonance analogy.

Findings

Pseudo-resonance peak exists in Raman spectra of spin ladders.

Peak width decreases with increasing spin S.

Resonance is tied to local minima in magnon spectrum.

Abstract

We argue that the Raman intensity in a spin S two-leg spin-ladder has a pseudo-resonance peak, whose width is very small at large S. The pseudo-resonance originates from the existence of a local minimum in the magnon excitation spectrum, and is located slightly below twice the magnon energy at the minimum. The physics behind the peak is similar to the excitonic scenario for the neutron and Raman resonances in a d-wave superconductor.