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 ρ~tα. 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<xc<0.265. Stressed rigid glasses (x>0.265) exhibit rather strong resistance drift, where the drift parameters increase steadily from α=0.13 for amorphous GeTe to α=0.29 for compositions near the stiffness threshold xc. On the other hand, the drift parameter in flexible glasses (x<0.25) decreases with decreasing Ge content x to values as low as α=0.05. These findings illustrate the strong impact of the stiffness threshold on resistance drift phenomena in chalcogenides. [ABSTRACT FROM AUTHOR]