Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 13: Electronic Structure of Surfaces II
O 13.6: Vortrag
Montag, 16. März 2015, 16:30–16:45, MA 041
Warping Effects on Spin and Electronic Structure of the Topological Surface State in α-Sn — •M. R. Scholz1, A. Fleszar2, G. Li2, F. Adler1, S. Glass1, L. Dudy1, J. Aulbach1, S. Muff3, J.-H. Dil3, M. Bianchi4, M. Michiardi4, P. Hofmann4, W. Hanke2, R. Claessen1, and J. Schäfer1 — 1Phys. Inst. and RCCM, Univ. Würzburg — 2Inst. f. Theo. Physik u. Astronomie, Univ. Würzburg — 3Swiss Light Source, Paul-Scherrer-Institut Villigen — 4Aarhus University
The strain-induced insulating phase of α-Sn was proposed to be of non-trivial topology in 2007 [1] and subsequently experimentally established by our group in 2013 [2]. Soon after the discovery of the topological insulators of the Bi2X3 family of materials the influence of the 3-fold symmetry of the crystal on spin texture and electronic structure of the topological surface state (TSS) has been dicussed, and is still a subject of current research. Here, we want to report on a detailed investigation of the influences of the diamond lattice symmetries on the TSS in α-Sn. Our results from angle-resolved photoemission show that the TSS deviates from the ideal shape of a Dirac cone with circular constant energy contours. Moreover, spin-resolved photoemission reveals a lifting of the perpendicular locking of spin and momentum similar to the case of Bi2X3, while, in contrast, the spin remains fully within the surface plane. The experimental results are in nice agreement with our own DFT calculations. [1] Fu and Kane Phys. Rev. B 76, 045302 (2007); [2] Barfuss et al., Phys. Rev. Letters 111, 157205 (2013)