Impact of Maxwell rigidity transitions on resistance drift phenomena in GexTe1-x glasses

Amorphous chalcogenides usually exhibit a resistivity, which increases with age following a power law rho similar to t(alpha). Existing theories link this change in amorphous state resistivity to structural relaxation. Here, the impact of fundamental glass properties on resistance drift phenomena in amorphous GexTe1-x networks is studied. Employing Raman spectroscopy, the Maxwell rigidity transition from flexible to stressed rigid is determined to occur in the compositional range 0.250<x(c)<0.265. Stressed rigid glasses (x>0.265) exhibit rather strong resistance drift, where the drift parameters increase steadily from alpha=0.13 for amorphous GeTe to alpha=0.29 for compositions near the stiffness threshold x(c). On the other hand, the drift parameter in flexible glasses (x<0.25) decreases with decreasing Ge content x to values as low as alpha=0.05. These findings illustrate the strong impact of the stiffness threshold on resistance drift phenomena in chalcogenides. (C) 2014 AIP Publishing LLC.