Excitation Spectrum of a Dimerized Next-Neighbor Antiferromagnetic Chain

Abstract

The excitation spectrum of an antiferromagnetic chain exhibiting the effects of both dimerization and frustration is studied. The method used is based on an exact solution for the doubly degenerate ground state, and views the excitations as propagating defect boundaries between the two exact ground states. These excitations are analogous to "solitons," and can bind into a second type of excitation, analogous to "breathers."