2025/07/05 by Maksym Parymuda, Parymuda, M. R.
Physics and Astronomy · #FOS: Physical sciences #Magnetic properties of thin films #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2507.04082
openalex publication_date 2025/07/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We present a detailed investigation of longitudinal magneto-thermal transport in the S=1/2 ferromagnetic XXZ model with easy-axis exchange anisotropy (Δ>1) on a face-centered cubic lattice consisting of four sublattices. We employ linear spin-wave theory and the Kubo formalism to evaluate the longitudinal spin and thermal conductivities, both of which exhibit activated temperature dependence in the low-temperature regime, and to determine their magnetic-field dependence. Our analysis indicates that a magnon gap is crucial for ensuring the convergence of these conductivities. Furthermore, by examining the ratio of thermal conductivity to spin conductivity, we identify an analog of the Wiedemann-Franz law for magnon transport at low temperatures. Finally, we demonstrate that these results can be generalized to systems with arbitrary spin.