Electronic structure and possible phase transition mechanism of different phases for perovskite structured AgNbO3

•Electronic structure, crystal structure and elastic properties of AgNbO3 for phases Pmc21, Pbcm, Cmcm, P4/mbm and Pm3m have been investigated.•The differences of electronic structure among phases are caused by the intensity of Nb-4d, O-2p and Ag-4d, 5 s orbitals hybridization.•The Nb-O bond and the torsion angle evolusions of NbO6 octahedron in different phases are attributed to the Jahn-Teller effect.•The crystal structural evolutions are correlated with the phase transition and the elastic constant matrix satisfies the condition of mechanical stability. Electronic structure, crystal structural evolution and elastic properties of AgNbO3 for phases Pmc21, Pbcm, Cmcm, P4/mbm and Pm3m have been investigated by first-principles calculations. The differences of electronic structure among phases are caused by the various intensity of Nb-4d, O-2p and Ag-4d, 5 s orbitals hybridization. The Nb-O bond and the torsion angle of NbO6 octahedron in different phases are investigated, and the lattice distortion can be attributed to the Jahn-teller effect. The crystal structural evolution among different phases is correlated with the phase transition closely. The elastic constant matrix of each phase satisfies the condition of mechanical stability. AgNbO3 is the ductile material and has the largest rigidity and the strongest volumetric strain resistance in the cubic phase.