Berlin 2015 – scientific programme
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DS: Fachverband Dünne Schichten
DS 29: Oxide and insulator surface: Structure, epitaxy and growth (joint session with O)
DS 29.2: Talk
Wednesday, March 18, 2015, 15:15–15:30, MA 042
Preparation of Bi2Se3(0001) surface studied by scanning tunneling microscopy — •Vasilii Sevriuk, Alberto Cavallin, Safia Ouazi, Dirk Sander, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
Despite the fact that the Bi2Se3(0001) surface is relatively inert [1], carbon is a common surface contaminant. It is detected by Auger electron spectroscopy (AES) and in scanning tunneling microscopy (STM) it appears as protrusions. Here we report the preparation of Bi2Se3(0001) by Ar sputtering and annealing and by in vacuo cleavage. We find by STM that sputtering and annealing cycles lead to surface and sub-surface defects, which can be ascribed to Se vacancies [2] and Bi interstitials [3]. After several cycles of sputtering and annealing, a periodic spatial modulation on the length scale of 10–15 nm is observed in STM constant current maps, which we ascribe to a dislocation network [4]. Samples prepared by cleavage do not show this spatial modulation.
[1] V. A. Golyashov, K. A. Kokh, S. V. Makarenko, K. N. Romanyuk, I. P. Prosvirin et al. J. Appl. Phys. 112, 113702 (2012).
[2] Y. S. Hor, A. Richardella, P. Roushan, Y. Xia, J. G. Checkelsky, A. Yazdani, M. Z. Hasan, N. P. Ong and R. J. Cava. Phys. Rev. B 79, 195208 (2009).
[3] S. Urazhdin, D. Bilc, S. H. Tessmer, S. D. Mahanti, Theodora Kyratsi, and M. G. Kanatzidis, Phys. Rev. B 66, 161306(R) (2002).
[4] M. Schmid, A. Biedermann, H. Stadler, and P. Varga. Phys. Rev. Lett. 69, 925 (1992).