title: Chiral asymmetry of the spin-wave spectra in ultrathin magnetic films.
abstract: We raise the possibility that the chiral degeneracy of the magnons in ultrathin films can be lifted due to the presence of Dzyaloshinskii-Moriya interactions. By using simple symmetry arguments, we discuss under which conditions such a chiral asymmetry occurs. We then perform relativistic first principles calculations for an Fe monolayer on W(110) and explicitly reveal the asymmetry of the spin-wave spectrum in the case of wave vectors parallel to the (001) direction. Furthermore, we quantitatively interpret our results in terms of a simplified spin model by using calculated Dzyaloshinskii-Moriya vectors. Our theoretical prediction should inspire experiments to explore the asymmetry of spin waves, with a particular emphasis on the possibility to measure the Dzyaloshinskii-Moriya interactions in ultrathin films.
authors.affiliation: Department of Theoretical Physics, Budapest University of Technology and Economics, H1111 Budapest, Hungary.
authors.forename: L
authors.initials: L
authors.lastname: Udvardi
authors.forename: L
authors.initials: L
authors.lastname: Szunyogh