Suppression of Ground-State Magnetization in Finite-Sized Systems Due to Off-Diagonal Interaction Fluctuations
Abstract
We study a generic model of interacting fermions in a finite-sized disordered system. We show that the off-diagonal interaction matrix elements induce density of states fluctuations which generically favor a minimum spin ground state at large interaction amplitude, . This effect competes with the exchange effect which favors large magnetization at large , and it suppresses this exchange magnetization in a large parameter range. When off-diagonal fluctuations dominate, the model predicts a spin gap which is larger for odd-spin ground states as for even-spin, suggesting a simple experimental signature of this off-diagonal effect in Coulomb blockade transport measurements.
Keywords
Cite
@article{arxiv.cond-mat/9909067,
title = {Suppression of Ground-State Magnetization in Finite-Sized Systems Due to Off-Diagonal Interaction Fluctuations},
author = {Philippe Jacquod and A. Douglas Stone},
journal= {arXiv preprint arXiv:cond-mat/9909067},
year = {2009}
}
Comments
Final, substantially modified version of the article. Accepted for publication in Physical Review Letters