Rashba spin-orbit coupling at surfaces

PD Dr. Jürgen Henk

Max Planck Institute of Microstructure Physics, Halle, Germany

Recently, spin-orbit coupling at surfaces has become a hot topic in surface science. The Rashba effect which leads to a unique spin topology of spin-orbit split surface states is investigated both experimentally and theoretically with great effort. In this presentation, I am going to present selected results of first-principles studies on systems with Rashba spin-orbit coupling.

After introducing the paradigmatic surfaces states in Au(111) and the giant spin splitting in surface alloys, e.g. Bi or Pb on Ag(111), I shall show that the physics of the Rashba effect is richer than is assumed in model calculations. Hybridization of electronic states, for example, produces an unconventional spin topology in Bi/Cu(111). Tuning of the spin splitting can be achieved in quantum wells, e.g. in Bi/Ag_n/Si(111), and by alloying, e.g. in Bi_xPb_1-x/Ag(111). A third approach is the deposition of Bi on a ferroelectric (BaTiO₃) in which the switching of the electric polarization controls the Rashba splitting. Eventually I am going to discuss the spin-orbit coupling at the Dirac point in graphene.