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arXiv · 2212.01084

Tuning metal/superconductor to insulator/superconductor coupling via control of proximity enhancement between NbSe$_2$ monolayers

Olivio Chiatti·Klara Mihov·Theodor U. Griffin·Corinna Grosse·Matti B. Alemayehu·Kyle Hite·Danielle Hamann·Anna Mogilatenko·David C. Johnson·Saskia F. Fischer
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Abstract

The interplay between charge transfer and electronic disorder in transition-metal dichalcogenide multilayers gives rise to superconductive coupling driven by proximity enhancement, tunneling and superconducting fluctuations, of a yet unwieldy variety. Artificial spacer layers introduced with atomic precision change the density of states by charge transfer. Here, we tune the superconductive coupling between NbSe$_2$ monolayers from proximity-enhanced to tunneling-dominated. We correlate normal and superconducting properties in [(SnSe)$_{1+δ}$]$_m$[NbSe$_2$]$_1$ tailored multilayers with varying SnSe layer thickness. From high-field magnetotransport the critical fields yield Ginzburg-Landau coherence lengths with an increase of 140 % cross-plane , trending towards two-dimensional superconductivity for m > 9. We show cross-over between three regimes: metallic with proximity-enhanced coupling, disordered-metallic with intermediate coupling and insulating with Josephson tunneling. Our results demonstrate that stacking metal mono- and dichalcogenides allows to convert a metal/superconductor into an insulator/superconductor system, prospecting the control of two-dimensional superconductivity in embedded layers.

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Olivio Chiatti, Klara Mihov, Theodor U. Griffin, Corinna Grosse, Matti B. Alemayehu, Kyle Hite, Danielle Hamann, Anna Mogilatenko, David C. Johnson, Saskia F. Fischer. 2022-12-02. Tuning metal/superconductor to insulator/superconductor coupling via control of proximity enhancement between NbSe$_2$ monolayers. https://doi.org/10.1088/1361-648x%2Facbf92

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