Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 51: Magnetism Poster B
MA 51.12: Poster
Donnerstag, 4. April 2019, 15:00–18:00, Poster C
Finding magnetic ground state of deposited clusters from first principles — •Balázs Nagyfalusi1, László Udvardi1, 2, and László Szunyogh1,2 — 1Department of Theoretical Physics, Budapest University of Technology and Economics, Budapest, Hungary — 2MTA-BME Condensed Matter Research Group, Budapest University of Technology and Economics, Budapest, Hungary
As the size of spintronic devices approaches the size of clusters containing few hundred of atoms the role of the simulations which are able to describe the magnetic properties of such a systems are more pronounced. We developed a method in the framework of the embedded cluster Green’s function method1 based on the the minimization of the overall torque on the magnetic moments. In order to find the local minimum we used the gradient descent method combined with the Newton-Raphson iteration where the torque and the Hessian matrix were calculated directly from first principles instead of relying on an effective spin Hamiltonian.
The procedure were applied on Fe trimers and on Fe chains deposited on Rh(111) surface. The geometry and the layer-layer distances were obtained from previous ab initio calculations. The sensitivity of the magnetic configuration on the geometry were studied by determining the ground state at different lattice relaxations. The overall results show the inherent symmetry and are more complex magnetic configuration than a trivial ferromagnetic alignment.
1 B. Lazarovits, L. Szunyogh and P. Weinberger, Phys. Rev. B 65, 104441 (2002)