Unraveling the spin structure of unoccupied states in Bi2Se3

Datzer C., Zumbülte A., Braun J., Förster T., Schmidt A., Mi J., Iversen B., Hofmann P., Minár J., Ebert H., Krüger P., Rohlfing M., Donath M.

Abstract

The optical control of spin currents in topological surface states opens new perspectives in (opto-) spintronics. To understand these processes, a profound knowledge about the dispersion and the spin polarization of both the occupied and the unoccupied electronic states is required. We present a joint experimental and theoretical study on the unoccupied electronic states of the topological insulator Bi2Se3. We discuss spin- and angle-resolved inverse-photoemission results in comparison with calculations for both the intrinsic band structure and, within the one-step model of (inverse) photoemission, the expected spectral intensities. This allows us to unravel the intrinsic spin texture of the unoccupied bands at the surface of Bi2Se3.