We consider an exchange model describing two isotropic spin-1/2 Heisenberg antiferromagnets coupled by a quartic term on the square lattice. The model is relevant for systems with orbital degeneracy and strong electron-vibron coupling in the large Hubbard repulsion limit, and is known to show a spin-Peierls-like dimerization in one dimension. In two dimensions we calculate energy gaps, susceptibilities, and con elation functions with a Green's function Monte Carlo method. We find a finite tripler and singlet gap, with no evidence of order of any kind. We conclude that the ground state is, most likely, a spin liquid of resonating valence bonds.

Spin-liquid ground state in a two-dimensional nonfrustrated spin model / Santoro, Giuseppe Ernesto; Sorella, Sandro; Guidoni, L; Parola, A; Tosatti, E.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 83:15(1999), pp. 3065-3068. [10.1103/PhysRevLett.83.3065]

Spin-liquid ground state in a two-dimensional nonfrustrated spin model

Santoro, Giuseppe Ernesto;Sorella, Sandro;
1999-01-01

Abstract

We consider an exchange model describing two isotropic spin-1/2 Heisenberg antiferromagnets coupled by a quartic term on the square lattice. The model is relevant for systems with orbital degeneracy and strong electron-vibron coupling in the large Hubbard repulsion limit, and is known to show a spin-Peierls-like dimerization in one dimension. In two dimensions we calculate energy gaps, susceptibilities, and con elation functions with a Green's function Monte Carlo method. We find a finite tripler and singlet gap, with no evidence of order of any kind. We conclude that the ground state is, most likely, a spin liquid of resonating valence bonds.
1999
83
15
3065
3068
https://arxiv.org/abs/cond-mat/9902116
Santoro, Giuseppe Ernesto; Sorella, Sandro; Guidoni, L; Parola, A; Tosatti, E.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/13507
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