近日，德国莱布尼茨固体与材料研究所的Sergey Borisenko及其研究团队取得一项新进展。经过不懈努力，他们揭示超导费米电弧的证据。相关研究成果已于2024年2月7日在国际权威学术期刊《自然》上发表。

通过结合角分辨光谱学和从头计算方法，该研究团队成功地在非中心对称的Weyl材料——三角PtBi₂的两个相对表面上识别出了拓扑费米弧。研究人员进一步发现，这些态在大约10K的温度下转变为超导态。值得注意的是，这些态的相干峰在固体光发射探测中表现出最强和最尖锐的激发特性。这一发现意味着PtBi₂中的超导性可能仅限于表面，从而使它成为在固有拓扑超导体-正常金属-超导体约瑟夫森结中容纳马约拉纳模式的潜在平台。

据悉，拓扑超导性是生产用于量子计算的马约拉纳费米子的关键要素。然而，体拓扑超导体仍然难以捉摸，因此，目前最有希望的方法是利用邻近诱导的超导性，但这种方法使系统变得脆弱且难以实现。另一方面，Weyl半金属因其固有的拓扑结构被视为潜在的候选材料，但一直与体超导性相关联，这导致人们忽视了其拓扑表面态可能具有的超导性，即费米弧。这种可能性在理论上也尚未得到充分关注。

附：英文原文

Title: Evidence of superconducting Fermi arcs

Author: Kuibarov, Andrii, Suvorov, Oleksandr, Vocaturo, Riccardo, Fedorov, Alexander, Lou, Rui, Merkwitz, Luise, Voroshnin, Vladimir, Facio, Jorge I., Koepernik, Klaus, Yaresko, Alexander, Shipunov, Grigory, Aswartham, Saicharan, Brink, Jeroen van den, Bchner, Bernd, Borisenko, Sergey

Issue&Volume: 2024-02-07

Abstract: An essential ingredient for the production of Majorana fermions for use in quantum computing is topological superconductivity. As bulk topological superconductors remain elusive, the most promising approaches exploit proximity-induced superconductivity, making systems fragile and difficult to realize. Due to their intrinsic topology, Weyl semimetals are also potential candidates, but have always been connected with bulk superconductivity, leaving the possibility of intrinsic superconductivity of their topological surface states, the Fermi arcs, practically without attention, even from the theory side. Here, by means of angle-resolved photoemission spectroscopy and ab initio calculations, we identify topological Fermi arcs on two opposing surfaces of the non-centrosymmetric Weyl material trigonal PtBi₂ . We show these states become superconducting at temperatures around 10K. Remarkably, the corresponding coherence peaks appear as the strongest and sharpest excitations ever detected by photoemission from solids. Our findings indicate that superconductivity in PtBi₂ can occur exclusively at the surface, rendering it a possible platform to host Majorana modes in intrinsically topological superconductor–normal metal–superconductor Josephson junctions.

DOI: 10.1038/s41586-023-06977-7

Source: https://www.nature.com/articles/s41586-023-06977-7