2004/11/30 by M. Arlego, Marcelo Arlego, Wilhelm Brenig +7
Physics and Astronomy · #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.dis-nn #cond-mat.str-el
paper · pdf · doi:10.1016/j.physb.2005.01.435
published as Physica B 359-361, 1424 (2005) · 2 pages, 1 figure. Proceedings of SCES'04, to appear in Physica B
arxiv created 2004/11/30 · openalex publication_date 2005/02/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the appearance of bound states in the spin gap of spin-1/2 ladders induced by weak bond disorder. Starting from the strong-coupling limit, i.e., the limit of weakly coupled dimers, we perform a projection on the single-triplet subspace and derive the position of bound states for the single impurity problem of one modified coupling as well as for small impurity clusters. The case of a finite concentration of impurities is treated with the coherent-potential approximation in the strong-coupling limit and compared with numerical results. Furthermore, we analyze the details in the structure of the density of states and relate their origin to the influence of impurity clusters.