Dynamics of the 1D Heisenberg model and optical absorption of spinons in cuprate antiferromagnetic chains

TL;DR

This paper develops a simple analytical model for the energy dynamical correlation function of the 1D Heisenberg antiferromagnetic chain, successfully explaining optical absorption spectra of spinons in cuprate chains.

Contribution

It introduces a new ansatz for the dynamical correlation function that accurately predicts optical absorption spectra in quasi-1D antiferromagnetic materials.

Findings

The ansatz reproduces recent infrared measurements in Sr$_2$CuO$_3$.

The model effectively describes phonon-assisted absorption spectra.

Numerical and analytical methods are combined for the first time in this context.

Abstract

We use numerical and analytical results to construct a simple ansatz for the energy dynamical correlation function of the 1D antiferromagnetic Heisenberg model. This is applied to compute the phonon assisted absorption spectra of magnetic excitations (spinons) in quasi-one dimensional spin 1/2 insulators and show to reproduce very well recent infrared measurements in Sr$_2$CuO$_3$.