2005/07/29 by Dariush Heidarian, Heidarian, Dariush, Mustansir Barma +3
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.dis-nn #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.cond-mat/0507701
4 pages, 4 figures
arxiv created 2005/07/29 · openalex publication_date 2005/07/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We show that the effect of disorder on a Mott-Hubbard insulator of interacting electrons produces a quantum phase transition from an antiferromagnetic to a paramagnetic phase governed by a percolation of the singly occupied weakly disordered sites. Near the transition, we propose that a new type of defect, formed by the resonant exchange between a spin singlet and a doubly occupied site with an attractive disorder potential, plays an important role. These resonant pair exchange defects reduce the staggered magnetization but enhance the coupling of the two spins and produce characteristic signatures in the temperature dependent specific heat and the non-Curie spin susceptibility, at temperatures on the order the hopping t, higher than the typical exchange scale J.