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1. Realizing a topological diode effect on the surface of a topological Kondo insulator

   https://doi.org/10.1073/pnas.2417709122  

   Zhang, Jiawen; Hua, Zhenqi; Wang, Chengwei; Smidman, Michael; Graf, David; Thomas, Sean; Rosa, Priscila_F_S; Wirth, Steffen; Dai, Xi; Xiong, Peng; et al (March 2025, Proceedings of the National Academy of Sciences)

   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, SmB ${}_6$, 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 $\mathit{pn}$-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. 

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2. Architectures of Topological Deep Learning: A Survey on Topological Neural Networks

   Papillon, Mathilde; Sanborn, Sophia; Hajij, Mustafa; Miolane, Nina (April 2023, Arxiv. Submitted to Transactions on Pattern Analysis and Machine Intelligence)
3. Topological Microlaser with a Non-Hermitian Topological Bulk

   https://doi.org/10.1103/PhysRevLett.131.023202  

   Li, Zhitong; Luo, Xi-Wang; Lin, Dayang; Gharajeh, Abouzar; Moon, Jiyoung; Hou, Junpeng; Zhang, Chuanwei; Gu, Qing (July 2023, Physical Review Letters)
4. Topological transformations of a nematic drop

   https://doi.org/10.1126/sciadv.adf3385  

   Koizumi, Runa; Golovaty, Dmitry; Alqarni, Ali; Li, Bing-Xiang; Sternberg, Peter J.; Lavrentovich, Oleg D. (July 2023, Science Advances)

   Morphogenesis of living systems involves topological shape transformations which are highly unusual in the inanimate world. Here, we demonstrate that a droplet of a nematic liquid crystal changes its equilibrium shape from a simply connected tactoid, which is topologically equivalent to a sphere, to a torus, which is not simply connected. The topological shape transformation is caused by the interplay of nematic elastic constants, which facilitates splay and bend of molecular orientations in tactoids but hinders splay in the toroids. The elastic anisotropy mechanism might be helpful in understanding topology transformations in morphogenesis and paves the way to control and transform shapes of droplets of liquid crystals and related soft materials. 

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5. Topological Hall Effect in a Topological Insulator Interfaced with a Magnetic Insulator

   https://doi.org/10.1021/acs.nanolett.0c03195  

   Li, Peng; Ding, Jinjun; Zhang, Steven S.-L.; Kally, James; Pillsbury, Timothy; Heinonen, Olle G.; Rimal, Gaurab; Bi, Chong; DeMann, August; Field, Stuart B.; et al (December 2020, Nano Letters)

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