A study of the potential barrier at the Σ13 (510) tilt boundary of strontium titanate using electron holography and dynamic simulation.

The phase shift of the exit electron wave function at the Σ13 (510) tilt boundary of strontium titanate (SrTiO₃) bicrystals was detected by electron holography. The results showed that there is a phase shift peak with a magnitude of ~0.3 rad at the centre of this grain boundary. Such a phase shift suggests that the potential barrier of ~3 V induced at the boundary core due to the interruption of the periodic potential of the crystal may be one of the intrinsic properties of grain boundary phenomena. Based on an electron dynamic diffraction, the phase of the exit electron wave function was simulated using a relaxed Σ13 (510) tilt boundary supercell with various occupancies of the atomic columns at the interface core. Coincidence of the measured and calculated results was achieved when the atomic columns are only half-occupied at the interface. [ABSTRACT FROM AUTHOR]