Chemically Tunable High Pressure Phase Transitions in Layered Si₂Te₃

Silicon telluride (Si₂Te₃) is a transparent-red, two-dimensional (2D) layered semiconductor that is of interest for its compatibility with silicon and for its unusual semiconducting opto-electronic and structural properties. Si2Te3 platelets were compressed to 12 GPa in a diamond anvil cell and measured with x-ray diffraction, Brillouin scattering, and Raman scattering. We show that Si₂Te₃ undergoes a semiconductor-to-metal electronic phase transition under pressure at 9.5 +/- 0.5 GPa coincident with a structural transition occurring at 8 +/- 0.5 GPa. Further, since silicon telluride is layered, we demonstrate a novel strategy to chemically tune the high pressure phase transition (both increasing and decreasing) through intercalation of zero-valent metals (Cu, Mn, Ge). This work demonstrates chemically tuning of thermodynamic behavior and addresses the high pressure phase behavior of silicon telluride.