High pressure studies on the electrical resistivity of Ge–Te–Tl glasses

Abstract

The variation of electrical resistivity in the system of glasses Ge 17 Te 83−x Tl x , with (1 ≤ x ≤ 13), has been studied as a function of high pressure for pressures up to 10 GPa. It is found that the normalized electrical resistivity decreases continuously with the increase in pressure and shows a sudden drop at a particular pressure (transition pressure), indicating the presence of a transition from semiconductor to near-metallic at these pressures which are in the range 3.0-5.0 GPa. This transition pressure is seen to decrease with the increase in the percentage content of thallium due to increasing metallicity of the thallium. The transition is reversible under application of pressure and X-ray diffraction of samples recovered after pressurization show that they remain amorphous after undergoing a pressurization decompression cycle.

Variation of Electrical Resistivity with High Pressure in Ge-Te-Sn Glasses: A Composition Dependent Study

“…2b) are nearly straight lines pointing to a nearly inverse linear correlation between tin content and the transition pressure. A decrease in transition pressure with the additive (thallium) content was observed in GeTeTl glasses also [22] but the beginning of the transition in the Tl containing glasses did not show a linear correlation as seen in the glasses containing tin.…”

“…Multi-component glasses such as GeSeBi [19], Ge TeAsS [20] exhibit continuous metallization whereas TlGeSe and TlTeGe glasses [21,22] have been found to show discontinuous metallization. It can be seen from the above that chalcogenide glasses belonging to dierent groups show interesting dierence in their pressure response, making high pressure studies on these materials an important tool in condensed matter physics.…”