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MM: Fachverband Metall- und Materialphysik

MM 34: Poster session II

MM 34.39: Poster

Dienstag, 21. März 2017, 18:30–20:30, P4

Effect of surface reconstruction on the exchange interactions in CaMnO3 — •Samara Keshavarz — Uppsala University, Uppsala, Sweden

The effects of geometrical relaxation at the surface as well as the change of crystal field are mostly able to influence the lower energy magnetic configuration. In particular, our analysis of CaMnO3 surface reveals that the exchange interaction between the Mn atoms belonging to the surface and the subsurface layers is very sensitive to the structural changes. An earlier study [A. Filippetti and W.E. Pickett, Phys. Rev. Lett. 83, 4184 (1999)] suggested that this coupling is ferromagnetic and gives rise to the spin flip process on the surface of CMO. In our work we confirm their finding for an unoptimised geometry, but once the structural relaxations are taken into account, this exchange coupling changes its sign and implies the surface of CMO to have the same G-type antiferromagnetic order as in the bulk. However, the suggested SF can be induced in the system by introducing an excess of electrons.