Quasielastic Neutron Scattering of Liquid Te₅₀Se₅₀ in the Semiconductor-to-Metal Transition Range

We have carried out neutron scattering experiments for liquid Te ₅₀Se₅₀ at 700K (semiconducting regime), 900K (transition regime) and 1100K (metallic regime). The quasielastic scattering peak is comparatively narrow at the peak positions of S(Q). A remarkable increase in the peak width is observed near the first minimum of S(Q), when the semiconductor-to-metal transition occurs. Since the first peak of S(Q) in this system proves to mainly reflect the inter-chain correlation and the second peak to the intra-chain correlation, the observed broadening may suggest frequent bond-switching between the chains in the metallic regime.