Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 93: Transport: Spintronics and Magnetotransport (Joint session of DS, HL, MA and TT, organized by TT)
HL 93.4: Vortrag
Donnerstag, 10. März 2016, 17:30–17:45, H23
Magnetic impurities on Bi thin films - conductivity and surface diffusion — •Philipp Kröger1, Sergii Sologub2, Andreas Lücke3, Nora Vollmers3, Uwe Gerstmann3, Wolf Gero Schmidt3, Herbert Pfnür1, and Christoph Tegenkamp1 — 1Leibniz Universität Hannover, Inst. für FKP, Appelstr. 2, 30167 Hannover — 2Inst. of Ph., Nat. Acad. of Sc., Nauky Av. 46, 03028 Kyiv, Ukraine — 3Universität Paderborn, Theoretische Materialphysik, Pohlweg 55, 33098 Paderborn
The semimetal bismuth has attracted a lot of interest because of its unique electronic properties such as low carrier concentration and large mobility. The surface states reveal a pronounced Rashba splitting. The surface conductivity can well be discriminated from bulk contributions for ultra-thin films grown epitaxially on Si(111) substrates, so that surface related effects are accessible even in macroscopic conductance measurements.
In this context, the adsorption of Cr with its high magnetic moment on the Bi(111) surface will be discussed. Cr induces a transition from Weak Anti- to Weak Localization. This indicates strong impurity scattering that mixes spin and orbit momenta, with corresponding symmetry breaking on the Bi surface (TRS), in agreement with results from DFT calculations. Contrary to other impurities adsorbed at subsurface sites (Fe,Co,Cr, Sb), Cr shows signs of diffusion processes at low T (T ≈ 10 K), as previously observed for Tb which adsorbes on the surface.