Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 42: Topological insulators (organized by O)
HL 42.6: Talk
Tuesday, April 1, 2014, 11:45–12:00, GER 38
Magnetic impurities on Bi thin films - Conductivity and surface diffusion — •Philipp Kröger1, Daniel Lükermann1, Sergii Sologub2, 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 Physik, 33098 Paderborn
The semimetal bismuth has attracted a lot of interest because of its unique electronic properties such as a low carrier concentration and a large mobility. The surface states reveal a pronounced Rashba splitting and the conductivity can be well discriminated from bulk contributions if thin films are grown epitaxially on Si(111) substrates, making surface related effects accessible even in macroscopic conductance measurements.
In this context the adsorption of the magnetic atom Cr (4,8 µB) on the Bi(111) surface will be discussed. In comparison to other adsorbates (Fe, Co, Tb) Cr exhibits the strongest scattering effect, accompanied by a transition from Weak Anti- to Weak Localization. This transition indicates strong impurity scattering, which lifts all spin-dependent selection rules. Furthermore, a significant increase of electron concentration due to hybridization effects has been found. For Tb and Cr surface diffusion of adsorbate-atoms even at T≈10 K needs to be considered.