Growth, characterization, and transport properties of ternary (Bi1−xSbx)2Te3 topological insulator layers. (17th October 2016)

• Record Type: Journal Article
• Authors: Weyrich, C; Drögeler, M; Kampmeier, J; Eschbach, M; Mussler, G; Merzenich, T; Stoica, T; Batov, I E; Schubert, J; Plucinski, L; Beschoten, B; Schneider, C M; Stampfer, C; Grützmacher, D; Schäpers, Th
• Is Part Of: Journal of physics. Volume 28:Number 49(2016)
• Publication Date: 2016-10-17
• Subjects: topological insulators -- molecular beam epitaxy -- Raman spectroscopy -- angular resolved photoemission spectroscopy -- low temperature -- magnetotransport; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/0953-8984/28/49/495501
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Ternary (Bi1− x Sb x )2 Te3 films with an Sb content between 0 and 100% were deposited on a Si(1 1 1) 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− x Sb x )2 Te3 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.