Revealing the role of magnetic disorder in phonon transport of monolayer CrOCl

In strongly coupled magnon-phonon systems, magnetic disorder plays a crucial role in shaping phonon properties and thermal transport behavior. However, conventional approaches typically rely on nonmagnetic (NM) approximations, neglecting the effects of magnetic ordering. To address the existing limitations, we propose an integrated computational framework that synergistically merges the special quasirandom structure (SQS) approach, first-principles calculations, and Boltzmann transport theory. This framework allows for a systematic exploration of the role of magnetic disorder in phonon thermal transport within monolayer CrOCl, with a particular focus on its impact on lattice thermal conductivity. Our results reveal that the transition from the ferromagnetic (FM) to paramagnetic (PM) phase strengthens harmonic interactions, leading to optical phonon hardening. Furthermore, this phase transition brings about marked alterations in lattice thermal conductivity. Through an in-depth analysis of relative errors in third-order interatomic force constants (IFC3), we attribute these changes to the complex impact of magnetic ordering on higher-order interactions, which, in turn, determine the strength of phonon-phonon scattering. This study establishes a robust framework for exploring thermal transport in magnetic materials and highlights the critical role of magnetic disorder in governing phonon-mediated heat conduction.