Ab initio study of 2DEG at the surface of topological insulator Bi2Te3
M. G. Vergniory+, T. V. Menshchikova*, S. V. Eremeev*×, E. V. Chulkov+°
+Donostia International Physics Center, 20018 Basque Country, Spain
*Tomsk State University, 634050 Tomsk Russia
×Institute of Strength Physics and Materials Science of the Siberian Branch of the RAS, 634021 Tomks, Russia
°Departamento de Fisica de Materiales UPV/EHU, 20080 Basque Country, Spain
Abstract
By means of ab initio DFT-calculation we analyze the
mechanism that drives the formation and evolution of the 2D electron
gas (2DEG) states at the surface of Bi2Te3 topological
insulator (TI). As it has been proved earlier it is due to an expansion of the van der Waals
(vdW) spacing produced by intercalation of adsorbates. We will show
that the effect of this expansion, in this particular surface,
leads to several intriguing phenomena. On one hand we observe a
different dispersion of the Dirac cone with respect to the ideal
surface and the formation of Parabolic Bands (PB) below the conduction band and
M-shaped bands in the valence
band, the latters have been observed recently in photoemission experiments.
On the other hand the expansion of the vdW-gaps changes the symmetry
of the orbitals forming the Dirac cone and therefore producing
modifications in the local spin texture. The localization of these
new 2DEG-states and the relocalization of the Dirac cone
will be studied as well.