Anomalous phase transition of Bi-doped Zn2GeO4 investigated by electrical conductivity and Raman spectroscopy under high pressure

We present a pressure-induced amorphization for pure and 0.5 mol. % Bi 3+ -doped Zn 2 GeO 4 samples, measured by high pressure Raman spectroscopy and high resolution transmission electron microscopy. Pressure-induced conductivity switching phenomena were discovered for both samples at around ∼7.01 GPa and ∼11.11 GPa, respectively, which closely correlated with the crystalline-to-amorphous transformation. The detailed conduction mechanism and the defect reaction process at high pressure indicate that the application of pressure could efficiently manipulate the microstructure and electrical performance of rare-earth doped polycrystalline materials, and therefore holds great promise for numerous applications in the future.