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Energy separation of single-particle and continuum states in a S=1/2 weakly-coupled chains antiferromagnet

A. Zheludev·M. Kenzelmann·S. Raymond·E. Ressouche·T. Masuda·K. Kakurai·S. Maslov·I. Tsukada·K. Uchinokura·A. Wildes
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Abstract

Inelastic neutron scattering is used to study transverse-polarized magnetic excitations in the quasi-one-dimensional S=1/2 antiferromagnet BaCu_2Si_2O_7, where the saturation value for the Néel order parameter is $m_0=0.12 μ_{\rm B}$ per spin. At low energies the spectrum is totally dominated by resolution-limited spin wave-like excitations. An excitation continuum sets in above a well-defined threshold frequency. Experimental results are discussed in the context of current theories for weakly-interacting quantum half-integer spin chains.

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A. Zheludev, M. Kenzelmann, S. Raymond, E. Ressouche, T. Masuda, K. Kakurai, S. Maslov, I. Tsukada, K. Uchinokura, A. Wildes. 2000-06-27. Energy separation of single-particle and continuum states in a S=1/2 weakly-coupled chains antiferromagnet. https://doi.org/10.1103/physrevlett.85.4799

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