Surface melting of deuterium hydride thick films
Zeppenfeld , P.
Bienfait , M.
Feng Chuan Liu ,
Vilches , O.E.
Coddens , G.
- Publisher: HAL CCSD
neutron diffraction examination of materials | deuterium | surface diffusion | [ PHYS.HIST ] Physics [physics]/Physics archives | melting | hydrogen | surface phase transformations | thin films
Quasi-elastic neutron scattering has been used to measure, below the bulk melting temperature, the thickness and the diffusion coefficient of the mobile surface layer of 8 and 10 layer thick films of deuterium hydride (HD) condensed on MgO(100). The measurements show that the close-packed surface of solid HD surface melts gradually, with the thickness of the melted layer increasing from 0.5 to 6 molecular layers as the temperature rises from 4 K to 0.05 K below the bulk melting temperature. The diffusion coefficients are in the 10-5 cm2 s-1 range indicating that the surface disordered film is liquid-like.