High transparency Bi2Se3 topological insulator nanoribbon Josephson junctions with low resistive noise properties

• Published in: Applied physics letters 2019-10, Vol.115 (17)
• Main Authors: Kunakova, Gunta, Bauch, Thilo, Trabaldo, Edoardo, Andzane, Jana, Erts, Donats, Lombardi, Floriana
• Format: Article
• Language: English
• Subjects: Applied physics; Critical current (superconductivity); Interfacial properties; Josephson junctions; Nanoribbons; Noise; Physical vapor deposition; Resistance; Superconductivity; Temperature dependence; Topological insulators; Transport; Tunnel junctions
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.5123554

Bi2Se3 nanoribbons, grown by catalyst-free Physical Vapor Deposition, have been used to fabricate high quality Josephson junctions with Al superconducting electrodes. The conductance spectra (dI/dV) of the junctions show clear dip-peak structures characteristic of multiple Andreev reflections. The temperature dependence of the dip-peak features reveals a highly transparent Al/Bi2Se3 topological insulator nanoribbon interface and Josephson junction barrier. This is supported by the high values of the Bi2Se3 induced gap and of IcRn (where Ic is the critical current and Rn is the normal resistance of the junction) product both of the order of 160 μeV, a value close to the Al gap. The devices present an extremely low relative resistance noise below 1 × 10−12 μm2/Hz comparable to the best Al tunnel junctions, which indicates a high stability in the transmission coefficients of transport channels. The ideal Al/Bi2Se3 interface properties, perfect transparency for Cooper pair transport in conjunction with low resistive noise, make these junctions a suitable platform for further studies of the induced topological superconductivity and Majorana bound states physics.