Pressure induced Ag₂Te polymorphs in conjunction with topological non trivial to metal transition

Silver telluride (Ag₂Te) is well known as superionic conductor and topological insulator with polymorphs. Pressure induced three phase transitions in Ag₂Te have been reported in previous. Here, we experimentally identified high pressure phase above 13 GPa of Ag₂Te by using high pressure synchrotron x ray diffraction method in combination with evolutionary crystal structure prediction, showing it crystallizes into a monoclinic structure of space group C2/m with lattice parameters a = 6.081Å, b = 5.744Å, c = 6.797 Å, β = 105.53°. The electronic properties measurements of Ag₂Te reveal that the topologically non-trivial semiconducting phase I and semimetallic phase II previously predicated by theory transformed into bulk metals for high pressure phases in consistent with the first principles calculations.