Abstract
We identify the multilayered compound GeBiTe to be a topological insulator with a Dirac point slightly above the valence band maximum, using angle-resolved photoemission spectroscopy (ARPES) measurements. The spin polarization satisfies the time reversal symmetry of the surface states, visible in spin-resolved ARPES. For increasing Sb content in GeBiSbTe we observe a transition from to type in bulk sensitive Seebeck coefficient measurements at a doping of . In surface sensitive ARPES measurements a rigid band shift is observed with Sb doping, accompanied by a movement of the Dirac point towards the Fermi level. Between and the Fermi level crosses the band gap, changing the surface transport regime. This difference of the - to -type transition between the surface region and the bulk is caused by band bending effects which are also responsible for a noncoexistence of insulating phases in the bulk and in the near surface region.
- Received 29 April 2013
DOI:https://doi.org/10.1103/PhysRevB.88.035407
©2013 American Physical Society