Semiconductor flexoelectricity in graphite-doped SrTiO3 ceramics

Improving the flexoelectric coefficients of materials is of great significance and challenge in physics and material sciences. Herein, graphite was roughly added into a paraelectric SrTiO3 (STO) ceramic, in order to increase the dielectric permittivity and electrical conductivity, which brings minimized variations to crystal, both structure and microstructure. More importantly, the flexoelectric coefficient of the doped STO with 20 wt% C was found to experience a jump increase by an order of magnitude relative with the pure STO, which could be well interpreted by the occurrence of an interface layer between the semiconductor surface and the electrodes, whereby under bending, a large macroscopic polarization in the paraelectric ferroelectrics was generated. The facile strategy in this paper introduces a general way to probing the semiconductor flexoelectricity in the paraelectric ferroelectrics.