Artículo
Large-S limit of the large-N theory for the triangular antiferromagnet
Zhang, Shang Shun; Ghioldi, Esteban Agustín
; Kamiya, Yoshitomo; Manuel, Luis Oscar
; Trumper, Adolfo Emilio
; Batista, C. D.
Fecha de publicación:
09/2019
Editorial:
American Physical Society
Revista:
Physical Review B: Condensed Matter and Materials Physics
ISSN:
1098-0121
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Large-S and large-N theories (spin value S and spinor component number N) are complementary, and sometimes conflicting, approaches to quantum magnetism. While large-S spin-wave theory captures the correct semiclassical behavior, large-N theories, on the other hand, emphasize the quantumness of spin fluctuations. In order to evaluate the possibility of the nontrivial recovery of the semiclassical magnetic excitations within a large-N approach, we compute the large-S limit of the dynamical spin structure factor of the triangular lattice Heisenberg antiferromagnet within a Schwinger boson spin representation. We demonstrate that, only after the incorporation of Gaussian (1/N) corrections to the saddle-point (N=∞) approximation, we are able to exactly reproduce the linear spin-wave theory results in the large-S limit. The key observation is that the effect of 1/N corrections is to cancel out exactly the main contribution of the saddle-point solution, while the collective modes (magnons) consist of two spinon bound states arising from the poles of the random phase approximation propagator. This result implies that it is essential to consider the interaction of the spinons with the emergent gauge fields and that the magnon dispersion relation should not be identified with that of the saddle-point spinons.
Palabras clave:
Large-S
,
Antiferromagnet
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Articulos(IFIR)
Articulos de INST.DE FISICA DE ROSARIO (I)
Articulos de INST.DE FISICA DE ROSARIO (I)
Citación
Zhang, Shang Shun; Ghioldi, Esteban Agustín; Kamiya, Yoshitomo; Manuel, Luis Oscar; Trumper, Adolfo Emilio; et al.; Large-S limit of the large-N theory for the triangular antiferromagnet; American Physical Society; Physical Review B: Condensed Matter and Materials Physics; 100; 10; 9-2019; 1-12
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