Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 42: Invited Talk: Gregor Mussler

HL 42.1: Hauptvortrag

Dienstag, 12. März 2013, 12:30–13:00, H2

MBE growth of topological insulator films and ARPES measurements — •Gregor Mussler, Jörn Kampmeier, Svetlana Borisova, and Detlev Grützmacher — Peter Grünberg Institute 9, Research Center Jülich

In this talk, we will present our results on molecular-beam epitaxy (MBE) of three dimensional topological insulators (TI) Bi₂Te₃, Bi₂Se₃, and Sb₂Te₃, as well as the ternary and quaternary alloys. By choosing proper growth parameters, single crystal epilayers with smooth surfaces and interfaces at the atomic level are grown. ARPES scans show the Dirac cone for all three material systems, evidencing the TI behavior of the MBE-grown epilayers. Besides, we will also present results on transport experiments. Due to naturally occurring defects, Bi₂Te₃ and Bi₂Se₃ are n-type doped, whereas Sb₂Te₃ is p-type doped. The ternary (Bi,Sb)₂Te₃ alloys show a change from n- to p-type doping for antimony concentrations between 25 - 40%. For these samples, we observed low bulk carrier concentrations, and features of surface carriers, such as weak antilocalization and Shubnikov-de Haas oscillations, were detected.