Dresden 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 31: TR: Nanoelectronics II - Spintronics and Magnetotransport 1 (jointly with HL and MA)
TT 31.6: Vortrag
Mittwoch, 16. März 2011, 12:15–12:30, HSZ 301
Magnetotransport measurements of Bi(111) thin films on Si(111) — •Daniel Lükermann1, Sergii Sologub2, Christoph Tegenkamp1, and Herbert Pfnür1 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, D-30167 Hannover — 2Academy of Science, Ukraine, 54 Volodymyrska St., Kiev, Ukraine
The semimetal bismuth has attracted a lot of interest because of its unique electronic properties such as the low carrier concentration and a large mobility of the carriers. Furthermore, the surface states reveal a pronounced Rashba splitting and the conductivity can be well discriminated from bulk contributions if thin films are grown on Si(111) substrates.
In this talk the magnetotransport properties of epitaxially grown Bi(111) thin films in the range of 10 to 40 bilayers (BL) on Si(111) will be presented. The films show positive magnetoresistance, i.e. decreasing conductance with magnetic field. The amplitude of the effect depends on the film thickness. We could observe different contributions from the surface state and the bulk in the magnetotransport measurements. A sharp peak in the magnetoconductance in the low B-field regime can be attributed to bulk holes and electrons with high mobility. For higher B-fields a nearly linear decrease of the conductance was found, stemming from carriers within the surface states. Measurements of the Hall-resistance show that mainly electrons contribute to the conductance of the surface state. The hole density is around two orders of magnitude smaller. As it turns out, even Bi films as thick as 40 BL are not fully charge compensated.