The electronic and structural properties in Ca2TiMnO6 double perovskite: The first principle study

Abstract

We studied the crystal structure of double perovskite Ca2TiMnO6 using ab initio density functional theory (DFT) calculations. We used the atomic positions given by the X-ray diffraction (XRD) data, in order to create a primitive lattice cell structure using visualization software Material Studio. Such sophisticated structure was found in tetragonal perovskite system, with space group with I4/m (#87) and lattice parameter of a = b = c = 5.32 Å. The exchange-correlation potential was treated with the Local Density Approximation (LDA) method. The calculations were performed with spin-polarization. The bandgaps for up-spin, net zero and down-spin were reported to be 1.051 eV, 0.988 eV and 1.806 eV respectively. The magnetic element Mn had an impact in tuning the bandstructure when the spin was induced. In summary, this double perovskite emits light when at the down spin state. The energy bandgap is opened, by 63 meV from net zero spin state to the up-spin state. Also, the PDOS illustration explains the reasons behind the changes in the bandstructure, between the up-spin, down-spin and net-zero spin, due to the shifts in the 3 d5 orbital states.