Surface states and second harmonic generation at the (110) nickel surface from a first-principles calculation

The electronic and magnetic structure of the ferromagnetic (1 1 0) nickel s urface is calculated within the first-principles Layer Korringa Kohn Rostoc ker (LKKR) method. Spin-dependent results are given for the local density o f states which show the existence of several empty surface states at the hi gh symmetry directions of the surface Brillouin zone. Unoccupied surface st ates with their dispersion are described in detail and compared with invers e photoemission measurements. Second harmonic generation can be calculated in magnetic systems within the framework of the LKKR method. We present pre liminary results which show that Surface states are responsible for an enha ncement of the second harmonic electric current in the vicinity of the (1 1 0) nickel surface. Such a surface state contribution to the second harmoni c signal has recently been observed in Ni(1 1 0). (C) 2001 Elsevier Science B.V. All rights reserved.