Quantization of Magnetic Excitation Continuum Due to Interchain Coupling in Nearly One-Dimensional Ising-Like Antiferromagnets

Abstract

The transverse magnetic excitation continuum of purely one-dimensional Ising-like antiferromagnets is formed from one magnon state and the odd-number-magnon (3-magnon, 5-magnon, …) bound states, which are mixed by the off-diagonal exchange interaction. The interchain molecular field causes a decoupling of these bound states and leads to quantization of the excitation continuum. This quantization effect can explain fine structures of magnon Raman spectrum of CsCoCl3 and CsCoBr3, which have been observed recently at low temperatures and remain unexplained so far.