近日，浙江大学焦琳团队在拓扑Kondo绝缘体表面实现了拓扑二极管效应。相关论文发表在2025年3月20日出版的《美国科学院院刊》杂志上。

将拓扑概念引入材料科学引发了从经典电子和光电子器件到拓扑量子器件的革命。后者具有以前所未有的效率传输能源和信息的潜力。研究组展示了三维材料SmB₆表面的拓扑二极管效应，SmB₆是一种候选拓扑Kondo绝缘体。在电磁调制和射频辐射下，二极管效应表现为明显的整流和光阀效应。

实验结果和建模表明，这些突出的效应与中温下拓扑表面态（TSS）的空间不均匀形成密切相关。这项工作提供了一种打破镜像对称性（除了反转对称性）的方法，从而在金属TSS的水坑之间形成pn结。这种效应为高效的电流整流器或能量收集装置在低温下工作到射频范围铺平了道路，使用具有大体积间隙的其他拓扑绝缘体可以将其扩展到高温。

附：英文原文

Title: Realizing a topological diode effect on the surface of a topological Kondo insulator

Author: Zhang, Jiawen, Hua, Zhenqi, Wang, Chengwei, Smidman, Michael, Graf, David, Thomas, Sean, Rosa, Priscila F. S., Wirth, Steffen, Dai, Xi, Xiong, Peng, Yuan, Huiqiu, Wang, Xiaoyu, Jiao, Lin

Issue&Volume: 2025-3-20

Abstract: Introducing the concept of topology into material science has sparked a revolution from classic electronic and optoelectronic devices to topological quantum devices. The latter has potential for transferring energy and information with unprecedented efficiency. Here, we demonstrate a topological diode effect on the surface of a three-dimensional material, SmB6, a candidate topological Kondo insulator. The diode effect is evidenced by pronounced rectification and photogalvanic effects under electromagnetic modulation and radiation at radio frequency. Our experimental results and modeling suggest that these prominent effects are intimately tied to the spatially inhomogeneous formation of topological surface states (TSS) at the intermediate temperature. This work provides a manner of breaking the mirror symmetry (in addition to the inversion symmetry), resulting in the formation of pn-junctions between puddles of metallic TSS. This effect paves the way for efficient current rectifiers or energy-harvesting devices working down to radio frequency range at low temperature, which could be extended to high temperatures using other topological insulators with large bulk gap.

DOI: 10.1073/pnas.2417709122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2417709122