Low-energy phases, electronic and optical properties of Bi1−xLaxFeO3 solid solution: Ab-initio LDA+U studies

Modification of BiFeO3 by substituting Bi (III) with La (III) was studied using ab-initio method based on self-interaction corrected local density approximation plus Hubbard-like U approach, as implemented in plane-wave pseudopotential Cambridge Serial Total Energy Package code. Possible stable phases of BiFeO3 and Bi1−xLaxFeO3 were determined from the calculated total energy. Phase transformation of rhombohedral to orthorhombic in Bi1−xLaxFeO3 solid solution occurred at 0.57 La concentration ratio for rhombohedral R3c and orthorhombic Pn21a phases, consistent with the available experimental and other calculation studies. The electronic band structure, density of states, and optical properties of Bi1−xLaxFeO3 were also investigated. Results showed that the electronic and optical properties of Bi1−xLaxFeO3 were mainly influenced by La concentration, but slightly affected by structural phase transformation. These results would provide a theoretical reference for fundamental science and technological application of Bi1−xLaxFeO3 solid solution.