Micro- and Nano-scale Thermal Measurement and Thermal Management Laboratory, School of Energy and Mechanical Engineering, Nanjing Normal University, Nanjing, 210023, P. R. China.
Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing, 211100, P. R. China.
Nanoscale Horiz. 2023 Jan 30;8(2):202-210. doi: 10.1039/d2nh00429a.
Active and reversible modulation of thermal conductivity can realize efficient heat energy management in many applications such as thermoelectrics. Using first-principles calculations, this study reports a giant thermal switching ratio of 12, much higher than previously reported values, in monolayer 2H-VSe above room temperature. Detailed analysis indicates that the high thermal switching ratio is dominated by the ferromagnetic ordering induced phonon bandgap, which significantly suppresses the phonon-phonon scattering phase space across the entire vibration spectrum. The thermal switching in bulk 2H-VSe is also investigated and the thermal switching ratio reaches 9.2 at the magnetic transition temperature. Both the phonon-phonon scattering space phase and phonon anharmonicity are responsible for the 9.2-fold thermal switching. This study advances the understanding of heat energy transport in two-dimensional ferromagnets, and also provides new insight into heat energy control and conversion.
通过使用第一性原理计算，本研究报告了在室温以上的单层 2H-VSe 中实现高效热能管理的巨大热开关比 12，远高于之前的报道值。详细分析表明，高的热开关比主要由铁磁有序引起的声子能带隙决定，这显著抑制了整个振动谱中的声子-声子散射相空间。还研究了体相 2H-VSe 的热开关，在磁转变温度下热开关比达到 9.2。声子-声子散射空间相和声子非谐性都导致了 9.2 倍的热开关。本研究推进了对二维铁磁体中热能输运的理解，也为热能控制和转换提供了新的见解。
