Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 51: Magnetism Poster B

MA 51.51: Poster

Donnerstag, 4. April 2019, 15:00–18:00, Poster C

Brillouin zone unfolding: Recovering information from supercell transmission maps — Michael Czerner, •Jonas F. Schäfer, Felix Scholler, and Christian Heiliger — Institut für Theoretische Physik, JLU Giessen

In order to accurately describe transport through tunnel barriers, it is often required to take perturbations into account. These could be chemical disorder, lattice defects, but also non-collinear magnetic structures in a ferromagnetic background. Within the NEGF formalism, which is implemented in our KKR code, it is possible to incorporate such effects using CPA with vertex corrections . However, it is sometimes more appropriate to describe the defect structure using supercells. In order to get a deeper insight into the underlying transport mechanism, it is often helpful to see k-resolved transmission maps. This method is not applicable for supercells, since here the information is contained in a much smaller BZ. To solve this issue we unfold the transmission into the specular and diffusive contribution, with a separate diffusive distribution map for each lead. This allows us to identify the relevant electronic states on both sides of the barrier even for k-scattering transport. As an example we take a look at a skyrmion in a thin magnetic iron layer adjacent to an MgO barrier. In this structure, the skyrmion may increase transport by allowing k-scattering to the Gamma-point.