Reversible polyamorphic transition inducing transformation from semiconductor to metal-like state in Te53.4Sn33Ga13.6 glass under moderate pressure

We report a reversible transformation from semiconductor to metal-like state in Te53.4Sn33Ga13.6 glass far lower than the common telluride crystallization/metallization pressure (∼7.0 GPa), accompanied by a resistance drop of more than four orders of magnitude. In situ high-pressure x-ray diffraction reveals a polyamorphic transition at ∼7.0 GPa from a low-density amorphous to a high-density amorphous state, characterized by ∼18.3% volume collapse and disappearance of the first sharp diffraction peak, indicating intermediate-range order breakdown. Molecular dynamics simulations show a distinct redistribution of coordination numbers near 7.0 GPa, while density functional theory calculations indicate pressure-induced electronic states at the Fermi level driving metallization. This work demonstrates that pressure-induced polyamorphism, without crystallization, can effectively tune the electrical properties of telluride glasses, offering valuable guidance for the electrical design of future thermoelectric devices.