Entropy of fermionic models on highly frustrated lattices
Abstract
Spinless fermions on highly frustrated lattices are characterized by a lowest single-particle band which is completely flat. Concrete realizations are provided by the sawtooth chain and the kagome lattice. For these models a real-space picture is given in terms of localized states. Furthermore, we find a finite zero-temperature entropy for a suitable choice of the chemical potential. The entropy is computed numerically at finite temperature and one observes a strong cooling effect during adiabatic changes of the chemical potential. We argue that the localized states, the associated zero-temperature entropy and thus also the large temperature variations carry over to the repulsive Hubbard model. The relation to flat-band ferromagnetism is also discussed briefly.
Cite
@article{arxiv.cond-mat/0511115,
title = {Entropy of fermionic models on highly frustrated lattices},
author = {A. Honecker and J. Richter},
journal= {arXiv preprint arXiv:cond-mat/0511115},
year = {2015}
}
Comments
10 pages including 5 figues; to appear in Condensed Matter Physics; proceedings of the conference "Statistical Physics 2005: Modern Problems and New Applications", Lviv, 28-30 August 2005