Regensburg 2013 – scientific programme

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O: Fachverband Oberflächenphysik

O 77: Electronic Structure and Spin-Orbit Interaction III

O 77.9: Talk

Thursday, March 14, 2013, 18:00–18:15, H33

Electronic properties of Bi overlayers on Au(111) studied by low-temperature scanning tunneling spectroscopy — •Pin-Jui Hsu, Jeannette Kemmer, Jens Kügel, Tobias Mauerer, and Matthias Bode — Institute of Experimental Physics II, University Würzburg, Am Hubland, 97074 Würzburg, Germany

The Au(111) surface state is the paradigm of a Rashba-Bychkov system which—due to the large atomic spin-orbit coupling—exhibits the largest spin-splitting of all nobel metals [1]. Recent experiments have shown that the Rashba-splitting can be further enhanced by the adsorption of heavy adatoms [2]. In addition, complex spin textures have been predicted around isolated magnetic surface impurities [3]. In this contribution, we present scanning tunneling spectroscopy (STS) data of ultra-thin Bi films grown on Au(111). Our results indicate that the electronic structure strongly depends on the actual Bi coverage and surface structure. While the STS spectrum of the so-called (6 × 6)-structure observed at a coverage of about 0.5 atomic layers (AL) is almost featureless, the monolayer exhibits a strong peak in the differential conductance at U = +2.3 V, i.e. in the unoccupied sample states. For a local Bi coverage of 2 AL an asymmetric peak is observed at U = +0.3 V. We will discuss the potential origin of these electronic features and analyze if they are subject to Rashba-splitting.
[1] S. LaShell et al., Phys. Rev. Lett. 77, 3419 (1996).
[2] C. R. Ast et al., Phys. Rev. Lett. 98, 186807 (2007).
[3] S. Lounis, A. Bringer and S. Blügel, Phys. Rev. B 108, 207202 (2012).