Thermal Conductivity of the Quasi One-Dimensional Spin System Sr_2_V_3_O_9_

TL;DR

This study measures thermal conductivity in Sr_2_V_3_O_9_ to identify the direction of spin-chains and the contribution of spinons, revealing that spinons significantly enhance conductivity along the [10-1] direction.

Contribution

It provides experimental evidence that spin-chains in Sr_2_V_3_O_9_ run along the [10-1] direction, based on thermal conductivity measurements under magnetic fields.

Findings

Peak in thermal conductivity around 10 K in zero field.

Magnetic field suppresses the peak along [10-1], indicating spinon contribution.

Spin-chains likely run along the [10-1] direction.

Abstract

We have measured the thermal conductivity along the [101] direction, kappa_[101]_, along the [10-1] direction, kappa_[10-1]_, and along the b-axis, kappa_b_, of the quasi one-dimensional S=1/2 spin system Sr_2_V_3_O_9_ in magnetic fields up to 14 T, in order to find the thermal conductivity due to spinons and to clarify whether the spin-chains run along the [101] or [10-1] direction. It has been found that both kappa_[101]_, kappa_[10-1]_ and kappa_b_ show one peak around 10 K in zero field and that the magnitude of kappa_[10-1]_ is larger than those of kappa_[101]_ and kappa_b_. By the application of magnetic field along the heat current, the peak of kappa_[10-1]_ is markedly suppressed, while the peaks of kappa_[101]_ and kappa_b_ little change. These results indicate that there is a large contribution of spinons to kappa_[10-1]_ and suggest that the spin-chains run along the [10-1] direction.