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arXiv · 1910.00280

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

Gunta Kunakova·Thilo Bauch·Edoardo Trabaldo·Jana Andzane·Donats Erts·Floriana Lombardi
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Abstract

Bi$_2$Se$_3$ nanoribbons, grown by catalyst-free Physical Vapour 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/Bi$_2$Se$_3$ topological insulator nanoribbon interface and Josephson junction barrier. This is supported by the high values of the Bi$_2$Se$_3$ induced gap and of I$_c$R$_n$ (I$_c$ critical current, R$_n$ normal resistance of the junction) product both of the order of 160 $\mu$eV, a value close to the Al gap. The devices present an extremely low relative resistance noise below 1$\times$10$^{-12}$ $\mu$m$^2$/Hz comparable to the best Al tunnel junctions, which indicates a high stability in the transmission coefficients of transport channels. The ideal Al/Bi$_2$Se$_3$ 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.

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Gunta Kunakova, Thilo Bauch, Edoardo Trabaldo, Jana Andzane, Donats Erts, Floriana Lombardi. 2019-10-01. High transparency Bi2Se3 topological insulator nanoribbon Josephson junctions with low resistive noise properties. https://doi.org/10.1063/1.5123554

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