Nonlinear Sigma model method for the J1-J2 Heisenberg model: disordered ground state with plaquette symmetry

2003/06/30 by Ken'ichi Takano, Yoshiya Kito, Yoshiaki Ono +1
Physics and Astronomy · #cond-mat.str-el #cond-mat.stat-mech #hep-th

paper · pdf · doi:10.1103/physrevlett.91.197202

published as Phys.Rev.Lett. 91 (2003) 197202 · 4 pages (including 2 figures)

arxiv created 2003/10/29 · arxiv updated 2009/11/30

Abstract

A novel nonlinear sigma model method is proposed for the two-dimensional J1-J2 model, which is extended to include plaquette-type distortion. The nonlinear sigma model is properly derived without spoiling the original spin degrees of freedom. The method shows that a single disordered phase continuously extends from a frustrated uniform regime to an unfrustrated distorted regime. By the continuity and Oshikawa's commensurability condition, the disordered ground states for the uniform J1-J2 model are plaquette states with four-fold degeneracy.

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