Diagonal and off-diagonal thermal conduction with resonant phonon scattering in Ni3TeO6

The coupling between phonon and magnon is ubiquitous in magnetic materials and plays a crucial role in many aspects of magnetic properties, most notably in spintronics. Yet, this academically and technologically interesting problem still poses a severe challenge to a general understanding of the issue in certain materials. We report that ${\mathrm{Ni}}₃\mathrm{Te}{\mathrm{O}}₆$ exhibits clear evidence of significant magnon-phonon coupling in both longitudinal thermal conductivity (${\ensuremath{\kappa}}_xx$) and thermal Hall coefficient (${\ensuremath{\kappa}}_xy$). The Debye-Callaway model, a phenomenological description for phonon heat conduction, can explain the measured magnetic field dependence of ${\ensuremath{\kappa}}_xx(H)$: phonon scattering from spin fluctuation in the paramagnetic phase and additional scattering due to magnon-phonon coupling in the collinear antiferromagnetic phase. We further suggest that a similar approach could be applied to understand the finite ${\ensuremath{\kappa}}_xy$ values in ${\mathrm{Ni}}₃\mathrm{Te}{\mathrm{O}}₆$.