近日，美国加州大学伯克利分校的Chris Dames及其研究小组与美国犹他大学的Mathieu Francoeur等人合作并取得一项新进展。经过不懈努力，他们对近场辐射传热的角和边缘模式增强现象进行了研究。相关研究成果已于2024年4月17日在国际权威学术期刊《自然》上发表。

本文从理论和实验两个角度深入剖析了，边角模式介导的近场辐射传热（NFRHT）的物理机制，并指出在“双纳米尺度”条件下，即当发射器和接收器的厚度及其间隙间距远小于热光子波长时，边角模式可以主导NFRHT过程。具体来说，对于间隔100纳米真空间隙的两种共面20纳米厚碳化硅膜，在室温下，其NFRHT系数预测和测量值高达830 W m^-2 K^-1，这一数值是同样间隔的真空间隙中两种无限大碳化硅表面NFRHT系数的5.5倍。

进一步考虑到两种共面膜之间的几何视图因子，该NFRHT系数竟是相应黑体极限的1400倍。这种显著的增强主要归功于电磁角模式和电磁边模式的贡献，它们共同占据了碳化硅膜间NFRHT的81%。这些发现对未来NFRHT在热管理和能量转换方面的应用具有重要意义。

据悉，近场辐射传热（NFRHT）已证实能够远超普朗克黑体极限，这得益于瞬变电磁阻挫模式和表面模式的隧穿现象，这一结论在多个实验中得到了验证，包括在两个大的平行表面之间以及两个亚波长膜之间的NFRHT实验。尽管如此，纳米结构在其角和边缘处能够维持更为丰富的局域电磁模式，但这些额外模式对于NFRHT的进一步增强潜力尚待发掘。

附：英文原文

Title: Corner- and edge-mode enhancement of near-field radiative heat transfer

Author: Tang, Lei, Corra, Lvia M., Francoeur, Mathieu, Dames, Chris

Issue&Volume: 2024-04-17

Abstract: It is well established that near-field radiative heat transfer (NFRHT) can exceed Planck’s blackbody limit by orders of magnitude owing to the tunnelling of evanescent electromagnetic frustrated and surface modes, as has been demonstrated experimentally for NFRHT between two large parallel surfaces and between two subwavelength membranes. However, although nanostructures can also sustain a much richer variety of localized electromagnetic modes at their corners and edges, the contributions of such additional modes to further enhancing NFRHT remain unexplored. Here we demonstrate both theoretically and experimentally a physical mechanism of NFRHT mediated by the corner and edge modes, and show that it can dominate the NFRHT in the ‘dual nanoscale regime’ in which both the thickness of the emitter and receiver, and their gap spacing, are much smaller than the thermal photon wavelengths. For two coplanar 20-nm-thick silicon carbide membranes separated by a 100-nm vacuum gap, the NFRHT coefficient at room temperature is both predicted and measured to be 830 W m^-2 K^-1, which is 5.5 times larger than that for two infinite silicon carbide surfaces separated by the same gap, and 1,400 times larger than the corresponding blackbody limit accounting for the geometric view factor between two coplanar membranes. This enhancement is dominated by the electromagnetic corner and edge modes, which account for 81% of the NFRHT between the silicon carbide membranes. These findings are important for future NFRHT applications in thermal management and energy conversion.

DOI: 10.1038/s41586-024-07279-2

Source: https://www.nature.com/articles/s41586-024-07279-2