Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 65: Methods: Theory and Experiment

O 65.1: Vortrag

Donnerstag, 28. Februar 2008, 12:00–12:15, MA 141

Quantum well states and Rashba-type spin-orbit splitting in ultrathin Bi films — •Gustav Bihlmayer¹, Yury M. Koroteev^2,3, Eugene V. Chulkov^3,4, and Stefan Blügel¹ — ¹Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany — ²Institute of Strength Physics and Materials Science, RAS, 634021, Tomsk, Russia — ³Donostia International Physics Center (DIPC), 20018 San Sebastiàn, Spain — ⁴Departamento de Física de Materiales, UPV/EHU, 20080 San Sebastiàn, Spain

In this contribution a systematic study of the electronic properties of thin (1−6 bilayers) films of the semimetal bismuth in (111) and (110) orientation is presented, employing calculations based on density functional theory. Due to the different coordination of the atoms in these two different surfaces, a large variation of the conducting properties of the films is found, ranging from small-bandgap semiconducting to semimetallic and metallic. The evolution of the Bi(111) and Bi(110) surface states is studied as a function of the film thickness and by comparison to thicker films and simulations of the semiinfinite crystals. Interesting features arise from the strong spin-orbit effects in Bi and the resulting Rashba-type spin-splitting of the surface states. The spin-polarization of these states can be seen to change as these states transform into quantum well states at the Brillouin zone boundary. These results will be compared with recent experimental results on thin Bi films on Si substrates.

[1] T. Hirahara et al., Phys. Rev. B 76, 153305 (2007)

[2] T. Hirahara et al., Phys. Rev. Lett. 97, 146803 (2006)