Tests of the two-state-system model in cold amorphous conductors

Abstract
The dynamics of atomic motions in the amorphous conductors Si-Au and C-Cu were probed using conductance fluctuations in mesoscopic samples in the temperature range 4300 K. Near 4 K the number of mobile sites was close to that expected from the anomalous heat capacity of amorphous materials.. Although some sites showed two-state-switching kinetics, a variety of statistical indicators all indicated that intersite interactions were important.