Spin-wave dispersion in a one-dimensional spin-½ Ising-like antiferromagnet

Abstract

Recently a number of experiments have been performed to study the spin dynamics of CsCoCl₃ which behaves like a spin-½ one-dimensional Ising-like antiferromagnet. Ishimura and Shiba (1980) have performed first-order perturbation calculations to explain various features of the spin dynamics for this system. Their first-order theory, however, does not give an adequate description of the experimental spin-wave dispersion and observed lineshape. In this work, the Ishimura-Shiba formalism is extended to the second order. Reasonable agreement is obtained with the experimental spin-wave dispersion. The lineshape is, however, modified only slightly from the lineshape obtained from the first-order theory.