Pressure And Temperature Dependence Of Raman Spectroscopy Of Solid Ionic Crystal Beta-K-0.294ga1.969o3

beta-gallate type compounds are promising solid-state ionic conductor, which has important application value in the field of energy storage. These compounds exhibit complex lattice dynamics due to the conducting layer tends to have an excess of alkali metal ions, which makes it difficult to further understand its conductive mechanism. Both pressure and temperature can affect the structure of materials by changing the spacing between atoms, and it has great application value in studying the dynamic process of materials, especially the diffusion process of ions. So far, the temperature dependence of vibrational properties has received less attention, and the high-pressure behavior of p-gallate type compounds has not been reported. Due to the unique advantage of laser Raman scattering technique in studying the lattice dynamics of matter, especially the pressure and temperature-dependent Raman spectroscopy, it is an effective experimental method for studying the lattice dynamics of the p-gallate type compounds. In this work, a novel p-gallate type K-0.234 Ga1.969O3 (KGO) crystal was successfully synthesized by using large-volume-press technology. The crystal was characterized by a scanning electron microscope, energy spectrum. The crystal structure of KGO is analyzed by single-crystal X-ray diffraction and compared with the crystal structure of beta-Ga2O3. The lattice dynamics of disordered alkali metal ions in the KGO conducting layer was studied by pressure and temperature dependent Raman spectroscopy. We found that the beta-gallate type KGO crystal structure formed by alternatively stacked-layer spinel-blocks and the loose conducting plane remains stable at the pressure up to 23. 3 GPa. The significant difference in the pressure coefficients between high and low-frequency Raman modes are derived from different types of vibration. It is evidenced that the presence of thermally activated processes K+ ions in KGO at approximately 300 degrees C, it' s embodied in the intensity of low-frequency Raman mode related to alkali metal K+ motion increases rapidly, while that of high-frequency vibration mode related to Ga-O polyhedron increases slowly. And the mobile K+ ions undergo disorder diffusion process along the conduction plane. Our results will contribute to a deeper understanding of the conductive mechanism of beta-gallate type compounds, and it is also very important to achieve accurate compositional control and doping of p-gallate type compounds.