0000000000077054
AUTHOR
B. Dupé
Mechanism for ultrafast electric-field driven skyrmion nucleation
We show how a Dzyaloshinskii-Moriya interaction can be generated in an ultrathin metal film from a femtosecond pulse in electric field. This interaction does not require structural inversion-symmetry breaking, and its amplitude can be tuned depending on the amplitude of the field. We perform first-principles calculations to estimate the strength of the field-induced magnetoelectric coupling for ferromagnetic Fe, Co, and Ni, and antiferromagnetic Mn, as well as FePt and MnPt alloys. Last, using atomistic simulations, we demonstrate how an isolated antiferromagnetic skyrmion can be coherently nucleated from the collinear background by an ultrashort pulse in electric field on a hundred-femtose…
Exchange Splitting of a Hybrid Surface State and Ferromagnetic Order in a 2D Surface Alloy
Surface alloys are highly flexible materials for tailoring the spin-dependent properties of surfaces. Here, we study the spin-dependent band structure of a DyAg$_2$ surface alloy formed on an Ag(111) crystal. We find a significant exchange spin-splitting of the localized Dy 4f states pointing to a ferromagnetic coupling between the localized Dy moments at $40\,$K. The magnetic coupling between these moments is mediated by an indirect, RKKY-like exchange coupling via the spin-polarized electrons of the hole-like Dy-Ag hybrid surface state.