Unified quantum mechanical picture for confined spinons in dimerized and frustrated spin S=1/2 chains

摘要

A quantum mechanical picture is presented to describe the behavior of confined spinons in a variety of S = 1/2 chains. The confinement is due to dimerization and frustration and it manifests itself as a nonlinear potential V(x) propor. to |x|~b, centered at chain ends (b <= 1) or produced by modulation kinks (b > 1). The calculation extends to weak or zero frustration some previous ideas valid for spinons in strongly frustrated spin chains. The local magnetization patterns of the confined spinons are calculated. A (minimum) enhancement of the local moments of about 11/3 over a single S = 1/2 is found. Estimates for excitation energies and binding lengths are obtained.