Berlin 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 28: Magnetic Thin Films III

MA 28.12: Vortrag

Donnerstag, 28. Februar 2008, 17:15–17:30, H 1012

Skyrmion states in confined condensed matter systems with intrinsic or surface-induced chirality — •Andrei A. Leonov^1,2, Igor E. Dragunov², Christian Pfleiderer³, Ulrich K. Rößler¹, and Alexei N. Bogdanov^1,2 — ¹IFW Dresden — ²Donetsk Institute for Physics and Technology — ³Physik Department E21, TU München

Chiral interactions stabilize smooth “Skyrmion” textures in ordered condensed matter systems. Unconventional Skyrmion states may be observable in magnetic nanostructures, where the chiral Dzyaloshinskii-Moriya exchange arises owing to reduced dimensionality and modified electronic properties of surfaces [1]. Similar surface effects exist also in ferroelectric layers and in confined liquid crystals. We develop a phenomenological theory for modulated and localized states in films of noncentrosymmetric ferromagnets and chiral liquid crystals with strong surface anisotropy or anchoring. Skyrmions with convex shape exist as localized and topologically stable excitations in collinearly ordered states of such films. The solutions for these two-dimensional “Baby-Skyrmions” are related to spherulitic domains in chiral nematic films. The theory describes Skyrmions with variable shapes. This variety is determined by the nature of the chiral coupling, which may arise due to broken inversion symmetry at surfaces or noncentrosymmetric crystal structures as in the chiral magnet MnSi [2].

[1] C. Pfleiderer, U.K. Rößler, Nature 447 (2007) 157; [2] U.K. Rößler, A. N. Bogdanov, C. Pfleiderer, Nature 442 (2006) 797.