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MA: Fachverband Magnetismus
MA 8: Magnetic Particles/ Clusters I
MA 8.5: Talk
Monday, March 14, 2011, 15:45–16:00, HSZ 103
Tight-binding theory of noncollinear magnetism in transition metal nanostructures: structural and interaction parameters dependence of clusters — •Pedro Ruiz-Díaz1, Raúl Garibay-Alonso1, Jesús Dorantes-Dávila2, and Gustavo Pastor1 — 1Institut für Theoretische Physik, Universität Kassel, Heinrich Plett Str. 40, 34132 Kassel, Germany — 2Instituto de Física, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, 78000 San Luis Potosí, Mexico
A self-consistent tight-binding electronic theory of noncollinear magnetism in nanostructures is presented and applied to transition metal clusters. The electronic structure is calculated by using a realistic rotational invariant tight-binding Hamiltonian and a real-space recursive expansion of the local Green’s functions. For free clusters with sizes N≤ 13, results are given for the ground-state local magnetic moments, magnetic order and average magnetic moments as a function of the Coulomb exchange integral J and d-band filling. A variety of qualitatively different complex noncollinear spin arrangements solutions are obtained which reveals the complex magnetic landscape in transition metal nanostructures. The onset of noncollinear magnetism is discussed by analyzing the stability of the various magnetic solutions. Structural effects are studied by considering representative compact and open geometries. Our calculations are compared with previous density-functional results. Substrate effects on the noncollinearity of the moments are discussed by considering deposited Fe3 clusters on Pt(111). Extensions and limitations of our work are also pointed out