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AM: Magnetismus

AM 17: Oberflächenmagnetismus: elektronische Eigenschaften, reine Oberflächen

AM 17.4: Vortrag

Mittwoch, 29. März 2000, 17:30–17:45, H22

Ab initio investigation of the effect of an applied electric field on the Fe(001) surface — •S. Clarke¹, X. Nie¹, M. Weinert², G. Bihlmayer¹ und S. Blügel¹ — ¹Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich. — ²Physics department, Brookhaven National Laboratory,Upton, New York 11973.

There exists in the literature a great deal of both theoretical and experimental work investigating the influence of applied electric fields on the electronic structure of metal surfaces. There is up until now however a lack of work investigating how an applied electric field affects the electronic structure of magnetic surfaces. This knowlegde would help us to understand the effects seen in magnetic tunnel junctions, systems which have recently seen great interest.

In this talk a method that allows a static applied electric field to be introduced into our film-FLAPW calculations is outlined and its use to investigate Fe(001) is described. We investigate the screening behaviour and whether the surface magnetic moment is field dependent. The behaviour of the total energy as a function of applied field is also investigated. A study of the stark shifts was carried out. Here it was observed that the stark shifts were different at different points in the Brillouin zone. This signifies that the effect of the electric field is more profound than simple Fermi filling – in order to account for the observed stark shifts, the applied field must alter the band-structure of the system.