The TRR 227 kindly invites you to a special TRR 227 Theory Seminar.

Speaker: Dr. Levente Rózsa, Universität Hamburg

Title: Tailoring magnetic skyrmions in ultrathin films

Abstract

Magnetic skyrmions have attracted significant research attention lately because of opening new possibilities for the energy-efficient storage, transport and processing of information in spintronics applications. Ab initio electronic structure calculations combined with classical spin model simulations have proven successful in describing the properties of skyrmions in ultrathin films consisting of a few atomic layers of magnetic material on nonmagnetic heavy metal substrates. The most widely investigated mechanism behind the stabilization of skyrmions is the Dzyaloshinsky-Moriya interaction, which is present at surfaces due to the presence of inversion symmetry breaking and the strong spin-orbit coupling in the substrate. Here we demonstrate how the interplay between frustrated Heisenberg exchange interactions and the Dzyaloshinsky-Moriya interaction modifies the interaction potential landscape for isolated skyrmions [1] and stabilizes localized configurations with different topological charges [2]. It is also discussed how atomic hydrogen adsorption may lead to the formation of skyrmions, as was demonstrated recently in two-atomic-layer-thick Fe films on Ir by scanning tunneling microscopy experiments [3].

[1] L. Rózsa, A. Deák, E. Simon, R. Yanes, L. Udvardi, L. Szunyogh, and U. Nowak, Phys. Rev. Lett. 117, 157205 (2016).

[2] L. Rózsa, K. Palotás, A. Deák, E. Simon, R. Yanes, L. Udvardi, L. Szunyogh, and U. Nowak, Phys. Rev. B 95, 094423 (2017).

[3] P.-J. Hsu, L. Rózsa, A. Finco, L. Schmidt, K. Palotás, E. Vedmedenko, L. Udvardi, L. Szunyogh, A. Kubetzka, K. von Bergmann, and R. Wiesendanger, Nat. Commun. 9, 1571 (2018).