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Spin dynamics in the $S=1/2$ weakly-coupled chains antiferromagnet BaCu$_2$Si$_2$O$_7$

A. Zheludev·M. Kenzelmann·S. Raymond·T. Masuda·K. Uchinokura·S. -H. Lee
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Abstract

Inelastic neutron scattering is used to identify single-particle and continuum spin excitations in the quasi-one-dimensional $S=1/2$ antiferromagnet \ba. In the data analysis, close attention is given to resolution effects. A gap in the continuum spectrum at $Δ_c=4.74.8$ meV is directly observed. The gap energy is in excellent agreement with existing theoretical predictions. Below the gap, the spectrum is dominated by sharp accoustic spin wave excitations.

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A. Zheludev, M. Kenzelmann, S. Raymond, T. Masuda, K. Uchinokura, S. -H. Lee. 2001-05-10. Spin dynamics in the $S=1/2$ weakly-coupled chains antiferromagnet BaCu$_2$Si$_2$O$_7$. https://arxiv.org/abs/cond-mat/0105223

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