Discovery of a novel spin structure


Today the interplay of exchange and Dzyaloshinskii-Moriya interaction (DMI) at transition-metal interfaces is a focus of research in condensed matter physics since it can lead to topologically non-trivial spin structures such as skyrmions and antiskyrmions which are promising for spintronic applications. Higher-order exchange interactions beyond pairwise Heisenberg exchange have received much less attention. The groups of Prof. Roland Wiesendanger (University of Hamburg) and of Prof. Stefan Heinze (CAU Kiel) now demonstrate based on spin-polarized scanning tunneling microscopy and density functional theory that higher-order exchange interactions can play a decisive role in transition-metal trilayers and that their competition with DMI can lead to novel types of spin structures (see figure). Their work recently published in Physical Review Letters "Competition of Dzyaloshinskii-Moriya and higher-order exchange interactions in Rh/Fe atomic bilayers on Ir(111)" also demonstrates that higher-order exchange needs to be taken into account in the search for novel transition-metal interfaces potentially promising for complex spin structures such as skyrmions.