title: Disorder induced quantum phase transition in random-exchange spin-1/2 chains.
abstract: We investigate the effect of quenched bond disorder on the anisotropic antiferromagnetic spin-1/2 (XXZ) chain as a model for disorder-induced quantum phase transitions. We find nonuniversal behavior of the average correlation functions for weak disorder, followed by a quantum phase transition into a strongly disordered phase with only short-range xy correlations. We find no evidence for the universal strong-disorder fixed point predicted by the real-space renormalization group, suggesting a qualitatively different view of the relationship between quantum fluctuations and disorder.
authors.affiliation: Forschungszentrum Karlsruhe, Institut für Nanotechnologie, 76021 Karlsruhe, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Hamacher
authors.forename: J
authors.initials: J
authors.lastname: Stolze
authors.forename: W
authors.initials: W
authors.lastname: Wenzel