Thermal Conductivity of the Spin Peierls Compound CuGeO_3

TL;DR

This study investigates how magnetic fields influence the thermal conductivity of CuGeO_3, revealing the interplay between spin excitations and phonons and their impact on heat transport in the Spin-Peierls compound.

Contribution

It provides the first detailed measurement of thermal conductivity of CuGeO_3 under high magnetic fields up to 16 T, highlighting the interaction between spin excitations and phonons.

Findings

Peak in thermal conductivity at 22 K above transition

Suppression of low-temperature peak under high magnetic fields

Spin-phonon scattering significantly affects heat transport

Abstract

The thermal conductivity of the Spin-Peierls (SP) compound CuGeO_3 was measured in magnetic fields up to 16 T. Above the SP transition, the heat transport due to spin excitations causes a peak at around 22 K, while below the transition the spin excitations rapidly diminish and the heat transport is dominated by phonons; however, the main scattering process of the phonons is with spin excitations, which demonstrates itself in an unusual peak in the thermal conductivity at about 5.5 K. This low-temperature peak is strongly suppressed with magnetic fields in excess of 12.5 T.