Absence of magnetic order for the spin-half Heisenberg antiferromagnet on the star lattice

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We study the ground-state properties of the spin-half Heisenberg antiferromagnet on the two-dimensional star lattice by spin-wave theory, exact diagonalization and a variational mean-field approach. We find evidence that the star lattice is (besides the \kagome lattice) a second candidate among the 11 uniform Archimedean lattices where quantum fluctuations in combination with frustration lead to a quantum paramagnetic ground state. Although the classical ground state of the Heisenberg antiferromagnet on the star exhibits a huge non-trivial degeneracy like on the \kagome lattice, its quantum ground state is most likely dimerized with a gap to all excitations. Finally, we find several candidates for plateaux in the magnetization curve as well as a macroscopic magnetization jump to saturation due to independent localized magnon states.
new extended version (6 pages, 6 figures) as published in Physical Review B

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Strongly Correlated Electrons, Statistical Mechanics

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http://salesiana.dossiersoluciones.com/handle/123456789/24110

Consulte el texto completo en el siguiente enlace:

https://arxiv.org/abs/cond-mat/0406103
 http://arxiv.org/abs/cond-mat/0406103
 Phys. Rev. B 70, 174454 (2004)
 doi:10.1103/PhysRevB.70.174454

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arXiv