科學家揭示殘余費米弧的手性籠目超導調制

作者：小柯機器人 發布時間：2024/8/25 18:54:32

本期文章：《自然》：Online/在線發表

近日，南方科技大學的殷嘉鑫與中國科學院物理研究所的石友國以及北京理工大學的王立志等人合作并取得一項新進展。經過不懈努力，他們揭示殘余費米弧的手性籠目超導調制。相關研究成果已于2024年8月21日在國際權威學術期刊《自然》上發表。

該研究團隊使用常規和約瑟夫森掃描隧道顯微鏡，在30毫開爾文的溫度下，以微電子伏特級別的電子能量差分辨率，在KV3Sb5和CsV3Sb5中檢測到了具有剩余費米弧的手性籠目超導性調制。研究人員觀察到了一個U形的超導間隙，其間隙內具有平坦的剩余態。該間隙顯示出具有磁場可調手性的2a × 2a空間調制，這與通過約瑟夫森隧穿觀察到的2a × 2a手性配對密度調制相一致。這些發現表明了一種打破時間反演對稱性的手性配對密度波（PDW）。

間隙內零能量態的準粒子干涉成像揭示了分段弧，高溫數據將其與電荷序中重建的釩d軌道態的部分聯系起來。檢測到的剩余費米弧可通過軌道間2a × 2a PDW對這些d軌道態的部分抑制來解釋，因此可作為玻戈留波夫費米態的候選。此外，研究人員將觀察到的PDW序與雜質誘導的間隙調制區分開來。這項觀察結果不僅揭示了具有軌道選擇性的手性PDW序，還展示了有限動量配對超導性中固有的基本空間-動量對應關系。

據悉，涉及有限動量配對的超導性可導致空間間隙和配對密度調制，以及超導間隙內的玻戈留波夫費米態。然而，在實驗上實現它們之間錯綜復雜的關系一直是個挑戰。

附：英文原文

Title: Chiral kagome superconductivity modulations with residual Fermi arcs

Author: Deng, Hanbin, Qin, Hailang, Liu, Guowei, Yang, Tianyu, Fu, Ruiqing, Zhang, Zhongyi, Wu, Xianxin, Wang, Zhiwei, Shi, Youguo, Liu, Jinjin, Liu, Hongxiong, Yan, Xiao-Yu, Song, Wei, Xu, Xitong, Zhao, Yuanyuan, Yi, Mingsheng, Xu, Gang, Hohmann, Hendrik, Holbk, Sofie Castro, Drrnagel, Matteo, Zhou, Sen, Chang, Guoqing, Yao, Yugui, Wang, Qianghua, Guguchia, Zurab, Neupert, Titus, Thomale, Ronny, Fischer, Mark H., Yin, Jia-Xin

Issue&Volume: 2024-08-21

Abstract: Superconductivity involving finite-momentum pairing can lead to spatial-gap and pair-density modulations, as well as Bogoliubov Fermi states within the superconducting gap. However, the experimental realization of their intertwined relations has been challenging. Here we detect chiral kagome superconductivity modulations with residual Fermi arcs in KV3Sb5 and CsV3Sb5 using normal and Josephson scanning tunnelling microscopy down to 30millikelvin with a resolved electronic energy difference at the microelectronvolt level. We observe a U-shaped superconducting gap with flat residual in-gap states. This gap shows chiral 2a × 2a spatial modulations with magnetic-field-tunable chirality, which align with the chiral 2a × 2a pair-density modulations observed through Josephson tunnelling. These findings demonstrate a chiral pair density wave (PDW) that breaks time-reversal symmetry. Quasiparticle interference imaging of the in-gap zero-energy states reveals segmented arcs, with high-temperature data linking them to parts of the reconstructed vanadium d-orbital states within the charge order. The detected residual Fermi arcs can be explained by the partial suppression of these d-orbital states through an interorbital 2a × 2a PDW and thus serve as candidate Bogoliubov Fermi states. In addition, we differentiate the observed PDW order from impurity-induced gap modulations. Our observations not only uncover a chiral PDW order with orbital selectivity but also show the fundamental space–momentum correspondence inherent in finite-momentum-paired superconductivity.

DOI: 10.1038/s41586-024-07798-y

Source: https://www.nature.com/articles/s41586-024-07798-y

期刊信息

Nature：《自然》，創刊于1869年。隸屬于施普林格·自然出版集團，最新IF：69.504

官方網址：http://www.nature.com/

投稿鏈接：http://www.nature.com/authors/submit_manuscript.html