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arXiv · 1511.00965

Growth, characterization, and transport properties of ternary (Bi1-xSbx)2Te3 topological insulator layers

C. Weyrich·M. Drögeler·J. Kampmeier·M. Eschbach·G. Mussler·T. Merzenich·T. Stoica·I. E. Batov·J. Schubert·L. Plucinski·B. Beschoten·C. M. Schneider·C. Stampfer·D. Grützmacher·Th. Schäpers
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Abstract

Ternary (Bi1-xSbx)2Te3 films with an Sb content between 0 and 100% were deposited on a Si(111) substrate by means of molecular beam epitaxy. X-ray diffraction measurements confirm single crystal growth in all cases. The Sb content is determined by X-ray photoelectron spectroscopy. Consistent values of the Sb content are obtained from Raman spectroscopy. Scanning Raman spectroscopy reveals that the (Bi1-xSbx)2Te3 layers with an intermediate Sb content show spatial composition inhomogeneities. The observed spectra broadening in angular-resolved photoemission spectroscopy (ARPES) is also attributed to this phenomena. Upon increasing the Sb content from x=0 to 1 the ARPES measurements show a shift of the Fermi level from the conduction band to the valence band. This shift is also confirmed by corresponding magnetotransport measurements where the conductance changes from n- to p-type. In this transition region, an increase of the resistivity is found, indicating a location of the Fermi level within the band gap region. More detailed measurements in the transition region reveals that the transport takes place in two independent channels. By means of a gate electrode the transport can be changed from n- to p-type, thus allowing a tuning of the Fermi level within the topologically protected surface states.

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C. Weyrich, M. Drögeler, J. Kampmeier, M. Eschbach, G. Mussler, T. Merzenich, T. Stoica, I. E. Batov, J. Schubert, L. Plucinski, B. Beschoten, C. M. Schneider, C. Stampfer, D. Grützmacher, Th. Schäpers. 2016-10-18. Growth, characterization, and transport properties of ternary (Bi1-xSbx)2Te3 topological insulator layers. https://doi.org/10.1088/0953-8984%2F28%2F49%2F495501

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