Spin Dynamics of a One Dimensional Ising-LikeAntiferromagnet in a Transverse Magnetic Field

Abstract

The effect of the transverse magnetic field h_x on the spin dynamics of a one dimensional Ising-like S=1/2antiferromagnet is discussed. Based on a picture of the propagating domain walls, we obtain dynamical spin correlation functions along the magnetic field S^xx(k, ω) and perpendicular to it S^yy(k, ω ). A remarkable effect is seen in S^yy(k, ω) for π/2 ≤ k \leπ, where the spectral weight moves toward the low energy side with the increase of h_x. The theory is applied to the analysis of the spin dynamics of CsCoCl₃, taking into account weak interchain interactions. Zeeman ladders occur and S^yy(k, ω) for k-- π exhibits a novel feature under the existence of h_x.