Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 21: Superconductivity: Poster Session
TT 21.8: Poster
Monday, March 16, 2015, 15:00–18:00, Poster B
Superconductivity in the ferecrystals [(SnSe)1+δ]m(NbSe2)1 — •Corinna Grosse1, Matti Alemayehu2, Georg Hoffmann1, Andreas Fiedler1, Olivio Chiatti1, Anna Mogilatenko1,3, David C. Johnson2, and Saskia F. Fischer1 — 1Novel Materials, Humboldt-Universität zu Berlin, 10099 Berlin, Germany — 2Department of Chemistry, University of Oregon, Eugene, OR, 97401, USA — 3Ferdinand-Braun-Institut, Leibniz-Institut fürHöchstfrequenztechnik, 12489 Berlin, Germany
The ferecrystals [(SnSe)1+δ]m(NbSe2)1 are novel layered materials consisting of single-layer NbSe2 sheets alternately stacked with m double layers of SnSe. NbSe2 exhibits interesting electrical properties such as charge density waves and superconductivity. In contrast to conventional misfit layer compounds, ferecrystals are turbostratically disordered and the individual layer thicknesses are tunable.
We investigate the structural and electrical properties of the ferecrystals [(SnSe)1+δ]m(NbSe2)1. The crystal structure was analyzed using scanning transmission electron microscopy, visualizing the ferecrystal layer structure on the atomic scale. The ferecrystals were characterized by measuring in-plane resistivity, magnetoresistance and Hall coefficients. A superconducting transition was observed in the resistivity measurements. The transition temperatures and the in-plane and cross-plane coherence lengths were investigated as a function of the thickness of the SnSe layers, which separate the NbSe2 single-layers. The relationship between the coherence lengths and the atomic structure of these quasi-two-dimensional materials is discussed.