Regensburg 2004 – scientific programme

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O: Oberflächenphysik

O 28: Postersitzung (Elektronische Struktur, Grenzfläche fest-flüssig, Halbleiteroberflächen und -grenzflächen, Magnetismus und Symposium SYXM, Methodisches, Nanostrukturen, Oberflächenreaktionen, Teilchen und Cluster, Zeitaufgelöste Spektroskopie)

O 28.19: Poster

Wednesday, March 10, 2004, 16:00–19:00, Bereich C

Ab-Initio-Investigation of Static and Magnetic Properties of Fe|GaAs(001) — •Harald Dobler and Dieter Strauch — Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg

We determine the structure and magnetic properties of the (001)-surface of GaAs covered by iron. Encouraged by our former investigations of the system Fe|ZnSe, where we have obtained dramatic deviations from the ideal structure as well as sensitivity of the magnetic properties to structural changes, we consider another example for the compound semiconductor. Again, the lattice constant of GaAs and the doubled value of α-Fe agree very well. Nevertheless, we find significant variations of the ideal behavior. We present our results for one, two, three, and four monolayers of iron. Similar to the case of Fe|ZnSe the effects are most interesting for a single monolayer. Therefore, we show the structures and the profiles of the density of valence electrons and the magnetization in the direction perpendicular to the interface.

The computations are carried out in the framework of spin polarized density functional theory implemented in the program package VASP [1,2]. Further, we use expansion in plane waves, ultrasoft pseudopotentials, and generalized gradient corrections (GGA). The relaxations of the structures are realized using a conjugate-gradient method.

[1] G. Kresse and J. Hafner, Phys. Rev. B 47, 558 (1993)

[2] G. Kresse and J. Furthmüller, Phys. Rev. B 54, 11169 (1996)