Long-range dynamics of magnetic impurities coupled to a two-dimensional Heisenberg antiferromagnet

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dc.creatorLuscher, Andreas
dc.creatorSushkov, Oleg P.
dc.date2004-08-27
dc.date2004-11-15
dc.date.accessioned2026-07-07T07:41:36Z
dc.date.available2026-07-07T07:41:36Z
dc.descriptionWe consider a two-dimensional Heisenberg antiferromagnet on a square lattice with weakly coupled impurities, i.e. additional spins interacting with the host magnet by a small dimensionless coupling constant g<<1. Using linear spin-wave theory, we find that the magnetization disturbance at distance r from a single impurity behaves as g/r for 1<<r<<1/g and as 1/(gr^3) for r>>1/g. Surprisingly the disturbance is inversely proportional to the coupling constant! The interaction between two impurities separated by a distance r is proportional to g^2/r for 1<<r<<1/g and to 1/r^3 for r>>1/g. Hence at large distances, the interaction is universal and independent of the coupling constant. We also find that the frequency of Rabi oscillations between two impurities is proportional to g^2 ln(gr) at 1<<r<<1/g, logarithmically enhanced compared to the spin-wave width. This leads to a new mechanism for NMR, NQR and EPR line broadening. All these astonishing results are due to the gapless spectrum of the magnetic excitations in the quantum antiferromagnet.
dc.description6 pages, 5 figures
dc.identifierhttps://arxiv.org/abs/cond-mat/0408598
dc.identifierhttp://arxiv.org/abs/cond-mat/0408598
dc.identifierPhys. Rev. B 71, 064414 (2005)
dc.identifierdoi:10.1103/PhysRevB.71.064414
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/122170
dc.subjectStrongly Correlated Electrons
dc.titleLong-range dynamics of magnetic impurities coupled to a two-dimensional Heisenberg antiferromagnet
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