Transport properties of a memory-type chalcogenide glass

Transport measurements have been performed on the conducting state of a memory-type chalcogenide glass, of composition Te81Ge15As4. DC resistivity was measured from 4°K to 300°K and indicates no carrier freeze-out occurs down to 4°K. The resistance ratio, ϱ(300°K)/ϱ(4°K), was found to be 2.5. AC conductivity measurements at room temperature showed only an 18% increase in σ(ω) up to 150 khz. Hall effect experiments at 100 Hz show no dependence of carrier concentration on temperature from 77°K to 300°K, and indicate a room temperature mobility of 85 cm2/V-sec. The sign of the Hall constant implies that the carriers are holes. Resistance was measured as a function of magnetic field from 0 to 140 kOe, at 1.6°K. The magnetoresistance was positive and proportional to H2 at low fields, with saturation beginning to set in above about 80 kOe. The results of these studies, taken in conjunction with the X-ray and NMR data, can be used to suggest a plausible model for memory behavior in chalcogenide glasses.