Nanocrystal Batio3：A Novel High-Pressure Cyclic Transformation Of Ion-Electron

Abstract

The electrical transport characteristics of nano BaTiO3 were systematically investigated under high pressures up to 35.64 GPa using AC impedance spectroscopy measurements and first-principles calculations. Impedance spectroscopy measurements provide insights into the conduction mechanism that involves cyclic ion-to-electron transformation induced by pressure. Through first-principles calculations, we have elucidated the underlying physical mechanisms responsible for the emergence of ion and electron conduction. This phenomenon arises from the distortion of electron density in the background around Ti and O atoms and a phase transition from tetragonal to cubic phase within a pressure range of 6.63 GPa to 10.61 GPa. These discontinuous changes are accompanied by alterations in initial resistance (R), relaxation frequency (F), and dielectric constant. By applying pressure, it becomes possible to effectively control the lattice spacing, thereby manipulating the charge density of OII ions and facilitating a seamless transition between ion and electron conduction pathways. Pressure modulation also regulates the migration behavior of O2- ions, leading to an enhancement in the conductivity of nano BaTiO3 materials. This study contributes towards advancing our understanding of cyclic transformation of ion-electron occurring within solid electrolytes.

Keywords: High-pressureNanocrystal BatiO3Electronic transport properties