Polarized neutron scattering investigation of excitations at low momentum transfer in liquid Ga: The mystery continues

New polarized neutron scattering experiments are presented on liquid gallium just above the melting transition of 303 K in order to shed light on the origin of the observed increased Ga cross-section at small scattering angles that has previously been reported in the literature. Our polarized neutron scattering experiments show that this increased cross-section cannot be linked to any magnetic or incoherent process, a linkage that was needed to justify the interpretation of this broad mode as being part of the cage-diffusion process. Instead, the increased cross-section has to be attributed to a coherent process, in violation of the measured sum-rules.

Research Highlights► Liquid metals exhibit unexplained excitations in scattering experiments. ► These excitations are only visible to neutrons, not to X-rays. ► Magnetic excitations appear to be a good explanation. ► We rule out magnetic excitations by doing polarized scattering on gallium. ► This leaves no viable explanation for the excess scattering.