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Phys. Rev. B 75, 134520 (2007) [6 pages]

Antiferromagnetism in two-dimensional t-J model: A pseudospin representation

Daisuke Yamamoto and Susumu Kurihara
Department of Physics, Waseda University, Okubo, Shinjuku, Tokyo 169-8555, Japan
Received 30 November 2006; revised 13 February 2007; published 30 April 2007

We discuss a pseudospin representation of the two-dimensional t-J model. We introduce pseudospins associated with empty sites, deriving a representation of the t-J model that consists of local spins and spinless fermions. We show, within a mean-field approximation, that our representation of t-J model corresponds to the isotropic antiferromagnetic Heisenberg model in an effective magnetic field. The strength and the direction of the effective field are determined by the hole doping delta and the orientation of pseudospins associated with empty sites, respectively. We find that the staggered magnetization in the standard representation corresponds to the component of magnetization perpendicular to the effective field in our pseudospin representation. Using a many-body Green's function method, we show that the staggered magnetization decreases with increasing hole doping delta and disappears at delta[approximate]0.06–0.12 for t/J=2.5–5. Our results are in good agreement with experiments and numerical calculations in contradistinction to usual mean-field methods.

©2007 The American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevB.75.134520
DOI: 10.1103/PhysRevB.75.134520
PACS: 74.72.-h; 71.27.+a; 71.10.Pm; 75.10.Jm
  • 74.72.-h
    Cuprate superconductors (high-Tc and insulating parent compounds)
  • 71.27.+a
    Strongly correlated electron systems; heavy fermions
  • 71.10.Pm
    Fermions in reduced dimensions (condensed matter) including anyons, composite fermions, Luttinger liquid, etc
  • 75.10.Jm
    Quantized spin models (magnetism)
  • YEAR: 2007
KEYWORDS: antiferromagnetism, Heisenberg model, t-J model, fermion systems, magnetisation, Green's function methods, spin systems

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