Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 32: 2D Materials I: Structure and Electronic Properties
O 32.10: Vortrag
Dienstag, 8. März 2016, 12:45–13:00, H24
Superconductivity in the ferecrystals (PbSe)1.14(NbSe2)n — •Corinna Grosse1, Matti B. Alemayehu2, Matthias Falmbigl2, Olivio Chiatti1, David C. Johnson2, and Saskia F. Fischer1 — 1Novel Materials Group, Humboldt-Universität zu Berlin, 12489 Berlin, Germany — 2Department of Chemistry, University of Oregon, Eugene, OR, 97401, USA
The ferecrystals (PbSe)1.14(NbSe2)n are artificially layered materials consisting of n NbSe2 single-layers stacked alternately with atomic double layers of PbSe. NbSe2 is a transition metal dichalcogenide with interesting electrical properties such as superconductivity and charge density waves. The influence of turbostratic disorder, a random rotation between the NbSe2 and PbSe layers, on the superconducting transition temperature has been unknown so far.
We investigate the structural and temperature-dependent electrical properties of the ferecrystals (PbSe)1.14(NbSe2)n by means of scanning transmission electron microscopy, X-ray diffraction, in-plane resistivity and Hall measurements and compare them to those of analogous non-disordered misfit layer compound (MLC) polymorphs. We observe a superconducting transition in the resistivity of the ferecrystals. The transition temperatures are reduced by up to 55 % with respect to the analogous MLC polymorphs. This indicates that turbostratic disorder substantially weakens the electron-phonon coupling in (PbSe)1.14(NbSe2)n. We discuss the results of the structural and electrical properties of the ferecrystals with respect to their MLC analogues and also with respect to ultra-thin NbSe2 layers.