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Topological excitations near a spinless atom in layered antiferromagnets with an axial magnetic field
Author(s) -
Fonseca M. P. P.,
Pereira A. R.
Publication year - 2003
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200301855
Subject(s) - condensed matter physics , physics , classical xy model , topological defect , spins , vortex , antiferromagnetism , spin (aerodynamics) , vortex state , magnetic field , ground state , plane (geometry) , isotropy , ferromagnetism , atom (system on chip) , anisotropy , phase transition , quantum mechanics , superconductivity , geometry , mathematics , thermodynamics , computer science , embedded system
We have investigated the effect of a nonmagnetic impurity on the configuration and energy of topological excitations in the isotropic two‐dimensional Heisenberg antiferromagnet in the presence of an external uniform magnetic field applied perpendicular to the XY plane. This model is expected to have the XY ‐like low‐temperature phase and show the Kosterlitz–Thouless transition due to a XY ‐like degeneracy of a canted spin‐flop ground state. The spins in the spin‐flop state may simultaneously tip into the out‐of‐plane directions while forming a vortex. Thus, we consider as the excitation for our study, the out‐of‐plane vortex. Our calculations show that an effective interaction between the two defects, the out‐of‐plane vortex and the nonmagnetic impurity, can be attractive at short range. These results can also be applied to two‐dimensional easy‐plane ferromagnets with weak anisotropy. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)