Evidence for Ballistic Thermal Conduction in the One-Dimensional S=1/2 Heisenberg Antiferromagnetic Spin System Sr2CuO3

TL;DR

This study demonstrates that spinons in the 1D S=1/2 Heisenberg antiferromagnetic spin system Sr2CuO3 conduct heat ballistically at low temperatures, confirming theoretical predictions through experimental measurements of thermal conductivity and magnetic susceptibility.

Contribution

First experimental evidence showing ballistic thermal conduction of spinons in a 1D quantum spin system, aligning with theoretical models.

Findings

Spinons exhibit mean free paths close to chain lengths between defects.

Thermal conduction by spinons is ballistic at low temperatures.

Impurities affect the spin chain length but not the ballistic nature of conduction.

Abstract

We have measured the thermal conductivity of the one-dimensional (1D) S=1/2 Heisenberg antiferromagnetic spin system of Sr2Cu1-xPdxO3 single crystals including nonmagnetic impurities of Pd2+. It has been found that the mean free path of spinons along the 1D spin chain at low temperatures is very close to the average length of finite spin chains between spin defects estimated from the magnetic susceptibility measurements. This proves that the thermal conduction due to spinons at low temperatures in Sr2CuO3 is ballistic as theoretically expected [Zotos et al.: Phys. Rev. Lett. 55 (1997) 11029].