Effect of orthorhombic distortion and electron correlation on the electronic structure of SrMnO3 from first principles

The total energies and electronic structures of SrMnO3 are studied from first principles calculations within the generalized-gradient approximation (GGA) framework. The orthorhombic structure with AFM1 configuration (see Fig. 1) is found to be the ground state of SrMnO3, consistent with the latest experimental observation. The orthorhombic distortion effect of SrMnO3 is studied by comparing its electronic structure and that of cubic structure, while correlation effect is evaluated by comparing GGA and GGA+UGGA+U calculations. In contrast to previous theoretical studies, our calculations show that both the orthorhombic distortion and the electron correlation play important roles in the electronic structure of SrMnO3.