SPIN-RESOLVED INVERSE-PHOTOEMISSION CALCULATIONS APPLIED TO CO(10(1)OVER-BAR0)

The one-step theory of photoemission in its version for several atoms per unit cell is applied to inverse photoemission calculations for the Co(10 ($) over bar 10) surface. Here we present the dispersion of Rydberg states along the Gamma Y-direction. By use of a spin-dependent surface barrier we observe an exchange splitting of about 100 meV for the first Rydberg state at Gamma. In an excellent agreement with the experimental data, the exchange splitting increases to 130 meV at the SBZ boundary ($) over bar Y.