Thermal Conductivity in the Frustrated Two-Leg Spin-Ladder System BiCu2PO6

TL;DR

This study investigates how thermal conductivity in BiCu2PO6 varies with temperature and magnetic field, revealing anisotropic behavior and possible spin state transitions in a frustrated two-leg spin-ladder system.

Contribution

It provides the first detailed measurements of thermal conductivity in BiCu2PO6 under magnetic fields, highlighting anisotropic effects and spin-related phenomena.

Findings

Thermal conductivity shows two peaks in zero field along all axes.

Thermal conductivity along the b-axis is significantly larger at high temperatures.

Magnetic fields induce kinks in thermal conductivity at ~7 T and ~10 T, indicating spin state changes.

Abstract

We have measured temperature and magnetic-field dependences of the thermal conductivity of single crystals of the frustrated two-leg spin-ladder system BiCu2PO6 in magnetic fields up to 14 T. It has been found that the temperature dependence of the thermal conductivity along every principal crystallographic axis shows two peaks in zero field but that the magnitude of the thermal conductivity along the b-axis parallel to spin ladders, $\kappa$b, is significantly larger than those of the thermal conductivity along the a-axis, $\kappa$a, and along the c-axis, $\kappa$c, at high temperatures above 7 K. These results suggest that the thermal conductivity due to spins probably exists only in $\kappa$b. Furthermore, it has been found that both magnetic-field dependences of $\kappa$a and $\kappa$b at 3 K show kinks at ~ 7 T and ~ 10 T, where the spin state may change.