Title: COOPERATIVITY, CAGE EFFECT AND HOPPING DIFFUSION IN SUPERCOOLED LIQUIDS AND GLASSES
Author(s): A.S.Bakai, N.P.Lazarev (National Science Center Kharkov Institute of Physics and Technology 1~Akademichna Str., 61108 Kharkov, Ukraine)

Molecular dynamic simulations of structure, thermodynamic and kinetic properties of model metallic Ag--Cu alloy are performed to elucidate its behavior at glass transition. In spite of small variations of inherent structure of the alloy the relaxation kinetics undergo dramatic changes at the glass transition. The time dependences of the mean square displacements and the non-Gaussianity parameter show the signs of anomalous diffusion in an intermediate time region. The analysis of time evolution of van Hove correlation function indicates the existence of both jump displacements and short-range cooperative atomic rearrangements. Below $T_{\mathrm{g}}$ these cooperative rearrangements do not contribute to a long-range diffusion but they still dominate the relaxation at short time.

Key words: glass transition, metallic alloys, cooperativity, anomalous diffusion
PACS: 61.20.Ja, 61.20.Lc, 64.70.Pf