Experimental evidence for fast heterogeneous collective structural relaxation in a supercooled liquid near the glass transition
We have extended the exploration of microscopic dynamics of supercooled liquids to small wave numbers Q corresponding to the scale of intermediate range order, by developing a new experimental approach for precise data correction for multiple scattering noise in inelastic coherent neutron scattering. Our results in supercooled Ca0.4K0.6(NO3)(1.4) reveal the first direct experimental evidence, after a decade of controversy, that the so-called picosecond process around the glass transition corresponds to a predicted first, faster stage of the structural relaxation. In addition, they show that this process takes the spatial form of fast heterogeneous collective flow of correlated groups of atoms.
Russina
M
Los Alamos National Laboratory, MS H805, Los Alamos, New Mexico 87545 and and Hahn-Meitner-Institute, Glienicker Strasse 100, 14109 Berlin, Germany.
Mezei
F
Lechner
R
Longeville
S
Urban
B