Spin Peierls gap [#!NishiPRB94!#,#!FujitaPRL95!#]

Nishi et al. observed the spin Peierls energy gap with inelastic neutron scattering measurements [143]. From the dispersion curve of the triplet excited state, the in-chain ($J_{\rm c}$) and the inter-chain ($J_{\rm a}$ and $J_{\rm b}$) magnetic coupling parameters were also obtained (shown in Fig.52). Fujita et al. performed neutron scattering measurements in magnetic fields up to 6 T [154]. They found the excited state split into three branches, indicating its triplet nature.