First-principles energy band calculation of Ruddlesden–Popper compound Sr3Sn2O7 using modified Becke–Johnson exchange potential

• Electronic structure of Sr3Sn2O7 is calculated on the basis of MBJ–LDA method for the first time.
• Band gap of Sr3Sn2O7 is determined accurately on the basis of MBJ–LDA method.
• The experimental absorption spectrum of Sr3Sn2O7 produced by MBJ–LDA is more accurate than that obtained by GGA method.

The electronic structure of Sr3Sn2O7 is evaluated by the scalar-relativistic full potential linearized augmented plane wave (FLAPW+lo) method using the modified Becke–Johnson potential (Tran–Blaha potential) combined with the local density approximation correlation (MBJ–LDA). The fundamental gap between the valence band (VB) and conduction band (CB) is estimated to be 3.96 eV, which is close to the experimental value. Sn 5s states and Sr 4d states are predominant in the lower and upper CB, respectively. On the other hand, the lower VB is mainly composed of Sn 5s, 5p, and O 2p states, while the upper VB mainly consists of O 2p states. These features of the DOS are well reflected by the optical transition between the upper VB and lower CB, as seen in the energy dependence of the dielectric function. Furthermore, the absorption coefficient estimated from the MBJ–LDA is similar to the experimental result.

Calculated energy band structure along the symmetry lines of the first BZ of Sr3Sn2O7 crystal obtained using the MBJ potential.Figure optionsDownload as PowerPoint slide