Dynamical tuning of the thermal conductivity via magnetophononic effects

Strategies for tuning the thermal conductivity of crystals by means of external fields are rare. Here, we predict the existence of large magnetophononic effects in materials that undergo antiferromagnetic (AFM) <-> ferromagnetic (FM) phase transitions, which allow for the modulation of the lattice heat conductivity, kappa(L), via the application of magnetic fields. Specifically, by using first-principles methods we predict a large and anomalous kappa(L) increase of approximate to 40% for the metamagnetic phase transition occurring in bulk FeRh near room temperature. The disclosed magnetophononic effects are caused by large anharmonic spin-phonon couplings, namely, significant differences in the phase space of allowed phonon-phonon collision processes taking place in the respective AFM and FM phases.