Low energy excitation in liquid Sb and liquid Bi observed in inelastic x-ray scattering spectra
Masanori Inui, Y. Kajihara, Shinya Hosokawa, Ayano Chiba, Yoichi Nakajima, Kazuhiro Matsuda, Jens R. Stellhorn, Toru Hagiya, Daisuke Ishikawa, Hiroshi Uchiyama, Satoshi Tsutsui, Alfred Q. R. Baron
Abstract
Abstract The dynamic structure factor S ( Q , E ), where Q and E are momentum and energy transfer, respectively, has been measured for liquid Sb, using inelastic x-ray scattering. A modified damped harmonic oscillator model function was applied to analyse S ( Q , E ) of liquid Sb and also to that of liquid Bi by Inui et al (2015 Phys. Rev. B 92 , 054206). The obtained excitation energy was in fairly good agreement with that predicted by ab initio molecular dynamics simulations on these liquid semi-metals. The excitation energy of the longitudinal acoustic mode in liquid Sb and liquid Bi exhibits flat-topped Q dependence whereas the lower excitation energy below the longitudinal acoustic excitation shows Q -gap behaviour. From the viscosity estimated from the Q -gap experimentally obtained, it is inferred that the lower energy excitation arises from the transverse acoustic excitation in the liquids.