title: Intrinsic surface dipole in topological insulators.
abstract: We calculate the local density of states of two prototypical topological insulators (Bi2Se3 and Bi2Te2Se) as a function of distance from the surface within density functional theory. We find that, in the absence of disorder or doping, there is a 2 nm thick surface dipole the origin of which is the occupation of the topological surface states above the Dirac point. As a consequence, the bottom of the conduction band is bent upward by about 75 meV near the surface, and there is a hump-like feature associated with the top of the valence band. We expect that band bending will occur in all pristine topological insulators as long as the Fermi level does not cross the Dirac point. Our results show that topological insulators are intrinsic Schottky barrier solar cells.
authors.affiliation: Department of Physics, University of California, Berkeley, CA 94720, USA.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Fregoso
authors.forename: Sinisa
authors.initials: S
authors.lastname: Coh