Field-dependent thermal transport in the Haldane chain compound NENP

TL;DR

This study investigates how magnetic fields influence thermal transport in the spin-1 chain compound NENP, revealing that quasiparticle motion remains effectively three-dimensional despite weak interchain interactions.

Contribution

It provides the first detailed analysis of field-dependent thermal conductivity in NENP using a quasiparticle model, highlighting the dimensionality of quasiparticle motion.

Findings

Thermal conductivity is highly sensitive to magnetic field changes.

Quasiparticle mean free path is temperature and momentum independent.

Quasiparticle motion is effectively three-dimensional despite weak interchain coupling.

Abstract

We present a study of the magnetic field-dependent thermal transport in the spin S=1 chain material Ni(C2H8N2)2NO2(ClO4) (NENP). The measured thermal conductivity is found to be very sensitive to the field-induced changes in the spin excitation spectrum. The magnetic contribution to the total heat conductivity is analyzed in terms of a quasiparticle model, and we obtain a temperature and momentum independent mean free path. This implies that the motion of quasiparticles is effectively three dimensional despite the tiny interchain coupling.