A PERTURBATION THEORY OF THE HEISENBERG ANTIFERROMAGNET
Abstract
The determination of some physical parameters of the ground state for the Heisenberg antiferromagnet is considered. The problem of more general lattices and of arbitrary spin is considered, and the long range order parameter is also treated. The results are reported in terms of series expansions generated by means of a modified Rayleigh-Schrodinger perturbation theory, which is proposed and developed in this dissertation. The modification amounts to a process whereby the definition of the zero-order Hamiltonian is changed through the prediction and inclusion of certain infinite classes of terms, whose first members appear in the original perturbation series. The final zero-order Hamiltonian obtained is the Ising model. Explicit expressions for the ground state parameters are given through fourth order for the liner chain, some quadratic, and simple cubic lattices with arbitrary spin. The calculation is carried through to determine the energy series through six orders also for the linear chain with spin one-half. A comparison with experimental determinations of the long range order in real antiferromagnets is made.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1963
- Accession Number
- AD0406249
Entities
People
- Donald L. Bullock
Organizations
- University of California, Los Angeles