Functional integral theories of low-dimensional quantum Heisenberg models
- 1 July 1988
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 38 (1), 316-332
- https://doi.org/10.1103/physrevb.38.316
Abstract
We investigate the low-temperature properties of the quantum Heisenberg models, both ferromagnetic and antiferromagnetic, in one and two dimensions. We study two different large-N formulations, using Schwinger bosons and S=(1/2 fermions, and solve for their low-order thermodynamic properties. Comparison with exact solutions in one dimension demonstrates the applicability of this expansion to the physical models at N=2. For the square lattice, we find at the mean-field level a low-temperature correlation length which behaves as ξ∝exp(A/T), where A asymptotically approaches 2π for large spin S, but ≃1.16 and ≃5.46. We mention the relevance of our results to recent experiments in .
Keywords
This publication has 35 references indexed in Scilit:
- Review of techniques in the large-expansion for dilute magnetic alloysReviews of Modern Physics, 1987
- Classical Heisenberg ferromagnet in two dimensionsPhysical Review B, 1987
- Mixed valence as an almost broken symmetryPhysical Review B, 1987
- Large-orbital-degeneracy expansion for the lattice Anderson modelPhysical Review B, 1987
- Few-dimensional Heisenberg ferromagnets at low temperaturePhysical Review Letters, 1987
- New Functional Integral Approach to Strongly Correlated Fermi Systems: The Gutzwiller Approximation as a Saddle PointPhysical Review Letters, 1986
- Kondo Bosons and the Kondo Lattice: Microscopic Basis for the Heavy Fermi LiquidPhysical Review Letters, 1986
- Quantum Heisenberg Ferromagnets in One and Two Dimensions at Low TemperatureProgress of Theoretical Physics Supplement, 1986
- On the solution of the Coqblin-Schreiffer Hamiltonian by the large-N expansion techniqueJournal of Physics C: Solid State Physics, 1983
- Nonlinear Field Theory of Large-Spin Heisenberg Antiferromagnets: Semiclassically Quantized Solitons of the One-Dimensional Easy-Axis Néel StatePhysical Review Letters, 1983