Elastic properties of cubic and rhombohedral<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>BiFeO</mml:mtext></mml:mrow><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>from first-principles calculations

First-principles elastic constants {c}_{\text{ij}}s of {\text{BiFeO}}_{3}with cubic nonmagnetic (NM)/ferromagnetic (FM) structures and rhombohedral antiferromagnetic (AFM) structure have been calculated within the generalized gradient approximation (GGA) and the \text{GGA}+Uapproach. In addition, the elastic properties of polycrystalline aggregates including bulk modulus and shear modulus are also determined and compared with...