Effective Hamiltonians and dilution effects in kagome and related antiferromagnets
Abstract
What is the zero-temperature ordering pattern of a Heisenberg antiferromagnet with large spin length (and possibly small dilution), on the kagome lattice, or others built from corner-sharing triangles and tetrahedra? First, I summarize the uses of effective Hamiltonians to resolve the large ground-state degeneracy, leading to long-range order of the usual kind. Secondly, I discuss the effects of dilution, in particular to {\it non}-frustration of classical ground states, in that every simplex of spins is optimally satisfied. Of three explanations for this, the most complete is Moessner-Chalker constraint-counting. Quantum zero-point energy may compete with classical exchange energy in a diluted system, creating frustration and enabling a spin-glass state. I suggest that the regime of over 97% occupation is qualitatively different from the more strongly diluted regime.
Cite
@article{arxiv.cond-mat/0009130,
title = {Effective Hamiltonians and dilution effects in kagome and related antiferromagnets},
author = {Christopher L. Henley},
journal= {arXiv preprint arXiv:cond-mat/0009130},
year = {2009}
}
Comments
11 pages; invited talk at "HFM 2000" (Waterloo, June 2000); submitted to Can. J. Phys