Magnon-Hole Scattering and Charge Order in $Sr_{14-x}Ca_xCu_{24}O_{41}$

TL;DR

This study investigates how hole doping affects magnon thermal conductivity in Sr14-xCaxCu24O41, revealing that charge ordering suppresses magnon-hole scattering, providing insights into charge-spin interactions in doped spin ladders.

Contribution

It introduces a novel method using magnon thermal conductivity to probe charge ordering and magnon-hole interactions in doped spin ladder materials.

Findings

Magnon mean free path strongly depends on doping and temperature.

Charge ordering leads to suppression of magnon-hole scattering.

Magnon thermal conductivity reveals local charge dynamics.

Abstract

The magnon thermal conductivity $\kappa_{\mathrm{mag}}$ of the hole doped spin ladders in $\rm Sr_{14-x}Ca_xCu_{24}O_{41}$ has been investigated at low doping levels $x$. The analysis of $\kappa_{\mathrm{mag}}$ reveals a strong doping and temperature dependence of the magnon mean free path $l_{\mathrm{mag}}$ which is a local probe for the interaction of magnons with the doped holes in the ladders. In particular, this novel approach to studying charge degrees of freedom via spin excitations shows that charge ordering of the holes in the ladders leads to a freezing out of magnon-hole scattering processes.