2008/04/30 by Vagson L. Carvalho‐Santos, V. L. Carvalho-Santos, A.R. Moura +3
Materials Science · Physics and Astronomy · #Magnetism in coordination complexes #Physics of Superconductivity and Magnetism #Theoretical and Computational Physics #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.77.134450
published as Phys. Rev. B 77 (2008) 134450 · 11 pages, 9 figures
openalex publication_date 2008/04/30 · arxiv created 2008/09/11 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the Heisenberg model of classical spins lying on a toroidal support, whose internal and external radii are r and R, respectively. The isotropic regime is characterized by a fractional soliton solution. Whenever the torus size is very large, R\ensuremath→\ensuremath∞, its charge equals unity and the soliton effectively lies on an infinite cylinder. However, for R=0, the spherical geometry is recovered and we obtain that configuration and energy of a soliton lying on a sphere. Vortexlike configurations are also supported: in a ring torus (R>r), such excitations present no core where energy could blow up. At the limit R\ensuremath→\ensuremath∞, we are effectively describing it on an infinite cylinder, where the spins appear to be practically parallel to each other, which yields no net energy. On the other hand, in a horn torus (R=r), a singular core takes place, while for R<r (spindle torus), two such singularities appear. If R is further diminished until it vanishesm we recover a vortex configuration on a sphere.