Large superconducting diode effect in ion-beam patterned Sn-based superconductor nanowire/topological Dirac semimetal planar heterostructures
Lê Đức Anh, Keita Ishihara, Tomoki Hotta, Kohdai Inagaki, Hideki Maki, Takahiro Saeki, Masaki Kobayashi, Masaaki Tanaka
Abstract
High-quality superconductor/topological material heterostructures are highly desired for realisation of topological superconductivity and Majorana physics. Here, we demonstrate a method to directly draw nanoscale superconducting β-Sn patterns in the plane of a topological Dirac semimetal (TDS) α-Sn thin film by irradiating a focused ion beam and taking advantage of the heat-driven phase transition of α-Sn into superconducting β-Sn. The β-Sn nanowires embedded in a TDS α-Sn thin film exhibit a large superconducting diode effect (SDE), whose rectification ratio η reaches a maximum of 35% when the magnetic field is applied parallel to the current. The results suggest that the SDE may occur at the α-Sn/β-Sn interfaces where the TDS α-Sn becomes superconducting by a proximity effect. Our work thus provides a universal platform for investigating quantum physics and devices based on topological superconducting circuits of any shape. Topological superconductivity may have important implications for fault-tolerant quantum computing, but its practical implementation remains challenging. Here, the authors report the fabrication of nanoscale heterojunctions based on superconducting β-Sn and topological Dirac semimetal α-Sn, showing superconducting diode rectification ratios up to 35%.