Evidence for Stoner-like behavior of the surface state on Gd(0001)

Abstract We report on angle-resolved photoemission and inverse photoemission studies of Gd(0001) in the temperature range 60 to 400 K. It is found that with increasing temperature both occupied and unoccupied parts of the d-like surface state at \ gG shift towards the Fermi level. This rules out a pure spin-mixing behavior with constant exchange splitting as claimed recently on the basis of spin-resolved PE data. Instead, the temperature variation of the surface-state exchange splitting is better described by a Stoner-like behavior, with an enhanced surface Curie temperature. Nevertheless, a small residual splitting above T c of the order of 100 meV cannot be ruled out.