Low-frequency transient dynamic clusters in simulated amorphous Ni0.5Zr0.5 around the glass temperature.
Molecular dynamics results are reported concerning cooperatively rearranging regions in simulated Ni0.5Zr0.5 melts down to 700 K . Emphasis is laid on discriminating between clusters of mobile atoms (CMA) from low-frequency dynamics and the all-frequency case, where the former characterize fluctuations and relaxations on the scale of the late beta regime and alpha decay, while the latter include, in addition, reversible high-frequency vibrations. Separation of the low-frequency part of the dynamics is carried out by low-pass filtering, exploiting the separation of time scales below the critical temperature T{c} of the mode-coupling theory. With increasing temperature, the low-frequency and all-frequency dynamics merge in the range of T{c} when the separation of time scales disappears. In the low-frequency CMA, the average size of correlated clusters of connected atoms turns out to be nearly one order of magnitude larger than in the all-frequency CMA. The low-frequency CMA appear as local clusters propagating extremely slowly in space with characteristic time scale of mus at 700 K , the scale of the onset of alpha decay.
Ladadwa
I
I
Institut für Materialphysik and SFB 602, Universität Göttingen, 37077 Göttingen, Germany.
Teichler
H
H