Calculation methods for thermal conductivity in non-equilibrium magnetic systems
磁性体系中热导的非平衡态计算方法

摘要

磁性绝缘体中热传导机制在自旋电子学与自旋热电子学中具有重要应用价值。近年研究发现，磁振子对热导率的贡献在铁磁与反铁磁材料中不可忽视，传统声子热导模型难以全面解释实验现象。本文在自旋动力学框架下，基于海森堡模型发展了适用于纯自旋体系的热流计算方法。我们首次推导出自旋构型驱动下非平衡稳态中的界面热流表达式，并结合郎之万自旋热浴机制，开发了能量追踪模块以验证公式准确性。本研究将热导频谱分析方法扩展至自旋动力学系统，为理解磁性材料中自旋激发对热输运的贡献提供了理论工具，也为今后磁性材料热导率的理论预测与实验对比建立新方法基础。

Abstract

Thermal transport in magnetic insulators plays a crucial role in spintronics and spin caloritronics. While magnon contributions to thermal conductivity are significant in both ferromagnetic and antiferromagnetic materials, conventional phonon-based models remain insufficient. Here, we develop a spin-dependent heat current formalism within the Heisenberg model framework. We derive, for the first time, the interfacial heat flux expression under spin-driven nonequilibrium steady states, validated through Langevin spin dynamics with an energy-tracking scheme. Our work extends spectral thermal analysis to spin systems, providing both a theoretical tool for understanding spin-mediated thermal transport and a new methodology for predicting magnetic material thermal conductivity.