Regensburg 2022 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: Superconductivity: Poster Session
TT 30.17: Poster
Thursday, September 8, 2022, 15:00–18:00, P1
Decoupling of NbSe2 monolayers in tailored SnSe-based multilayers — •O. Chiatti1, K. Mihov1, T. Griffin1, C. Grosse1, M. B. Alemayehu2, K. Hite2, D. Hamann2, A. Mogilatenko3, D. C. Johnson2, and S. F. Fischer1 — 1Novel Materials Group, Humboldt-Universität zu Berlin, 10099 Berlin, Germany — 2Solid State Chemistry, University of Oregon, Eugene OR 97403-1253, U.S.A. — 3Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
Van-der-Waals superlattices with two-dimensional (2D) superconducting layers of a transition-metal dichalchogenide (TMD) embedded between other materials have received a lot of attention [1].
Here, we examine the coupling between the NbSe2 monolayers in [(SnSe)1+δ]m[NbSe2] ferecrystals [2].
m is an adjustable parameter to control the spacing between NbSe2 layers and tune the inter-layer coupling, with a crossover from 3D to 2D superconductivity.
The electric transport shows three regions:
I. for m = 1−4 the films resemble “good” metals and 3D anisotropic superconductors, with inter-layer coupling enhanced by proximity effect in the SnSe layers and charge transfer from NbSe2 to SnSe;
II. for m = 5−9 the films are “dirty” metals and 3D anisotropic superconductors, with inter-layer coupling reduced by disorder and smaller charge transfer;
III. for m > 9 they are “bad” insulators and a stack of disordered quasi-2D superconductors, with Josephson coupling between NbSe2 monolayers.
[1] A. Devarakonda et al., Science 370, 231 (2020)
[2] M. Trahms et al., Supercond. Sci. Technol. 31, 065006 (2018)