Continuum of spin excitations in an ordered magnet
Jieming Sheng, Le Wang, Wenrui Jiang, Han Ge, Nan Zhao, Tiantian Li, Maiko Kofu, Dehong Yu, Wei Zhu, Jia‐Wei Mei, Zhentao Wang, Liusuo Wu
Abstract
Spin excitation continua observed in neutron scattering studies are often considered to be strong evidence of quantum spin liquid formation. In a disorder-free magnetic compound with a quantum spin liquid ground state, the elementary excitation is no longer the conventional spin waves (magnons). Instead, the magnons fractionalize into spinons, producing a characteristic two-spinon continuum. However, it remained uncertain whether a clean, ordered antiferromagnet could exhibit a continuous spectrum similar to that of a quantum spin liquid. This paper presents evidence of a spin excitation continuum in the magnetically ordered state of Na 2 BaCo(PO 4 ) 2 , where free spinons are absent. This challenges the interpretation of such a continuum as a definitive signature of a quantum spin liquid in new material studies.