Regensburg 2022 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 25: Transport Properties
DS 25.4: Vortrag
Donnerstag, 8. September 2022, 15:45–16:00, H14
Parallel field magnetoconductance in epitaxial bismuth quantum films — •Julian Koch1, Doaa Abdelbarey2, Philipp Kröger2, Priyanka Yogi2, Christoph Tegenkamp1, and Herbert Pfnür2 — 1Institut für Physik, TU Chemnitz, Reichenhainerstr. 70, 09126 Chemnitz — 2Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover
The magnetoconductance (MC) of epitaxial Bi films on Si(111) (thickness 20-100 bilayers) was measured at T=9 K in magnetic fields oriented in-plane parallel and perpendicular to the electric dc current I. Contributions to MC by weak antilocalization (WAL), by weak localization (WL) as well as by diffuse scattering were identified, which all turned out to be independent of the angle between B and I. In addition, only for B ⊥ I a contribution to MC was found that increases with increasing B and is, to first approximation, ∝ B2. It is ascribed to ballistic scattering between the Rashba-split interfaces that allow Umklapp scattering without spin flip.
At small thicknesses the MC curves are dominated by WAL originating from the surface/interface states. However, the coupling between the interfaces, necessary for the observation of WAL in an in-plane B-field, happens through quantized bulk states instead of tunneling. Moreover, the admixing of the quantized bulk states with increasing film thickness not only increases diffuse scattering, but also modifies the WAL component, effectively introducing a WL-like component, above 50 BL. Thus, our findings suggest an intriguing interplay in magnetotransport between 2D and quantized 3D states.