Electronic and optical properties of the R3 Ni3TeO6 compound described by the modified Becke-Johnson exchange potential

Abstract

Calculations based on the density functional theory (DFT) have been realized to study the electronic and optical properties of the Ni3TeO6 compound with a hexagonal crystal structure (R3 space group). Exchange and correlation electronic effects were described by a modified Becke-Johnson (mBJ) potential in its semiconductor variance form. The collinear antiferromagnetic state of the R3 Ni3TeO6 compound was simulated. The calculated spin magnetic moment of the Ni atoms (1.65 μB) was found to be in good agreement with the experimental result (2.03 μB). Moreover, the calculated optical band gap (2.8 eV) agreed well with the experimental prediction (2.5 eV). These facts suggest a reliable electronic structure description of the material. Hence, we also calculated the complex dielectric function, optical absorption spectrum, refractive index, and extinction coefficient. The optical absorption spectrum was interpreted based on the determined electronic structure. The direct optical absorption edge of the material was characterized by the electronic transitions from O 2p states to Te 5s states and from Ni 3d states to O 2p states. This description did not agree with previous ones based on DFT + U calculations or those made based on the electronic structure of the Ni3V2O8 compound. Thus, an alternative description of the electronic structure of the R3 Ni3TeO6 compound in its antiferromagnetic state using the DFT + mBJ calculations has been suggested, and consequently a new origin for the optical absorption observed around the optical band gap.