Maximum Entropy Method Applied in the Experimental Visualization of Electron Density Distributions in BiFeO3

Abstract

The BiFeO3 is a largely studied compound with magnetoeletric coupling at room temperature. This is due its potential technological applications that can be directly used in advanced technologies. BiFeO3 is an oxide with perovskite structure and R3c space group (rhombohedral symmetry). In this work, synchrotron radiation X-ray powder diffraction data was used to obtain a detailed description of BiFeO3 crystal structure. Thereafter, experimental electron density distribution calculations were obtained using by the maximum entropy method (MEM) statistical approach. The ionic/covalent nature of the bonding and the interaction between the ions are clearly revealed by constructing electron density maps. The Fe3+-O2− and Bi3+-O2− bonding were studied in 1 and 2 dimensional electron density distributions. Due the high resolution of the obtained maps, it can be regarded as the most precise electron density distributions seen inside the material.