Temperature dependence Raman spectroscopy and DFT calculations of Bi2(MoO4)3.

ABSTRACT

This work reports a theoretical and experimental study on the electronic and vibrational properties of Bi2(MoO4)3. First-principle calculations were applied to increase the understanding on the properties of the chemical composition through the energy bands. The conduction band minimum (CBM) is found at the high symmetric Γ-point, while the valence-band maximum (VBM) is located between the Z and the Γ-points. Therefore, these facts confirm that the Bi2(MoO4)3 crystal is a semiconductor compound with an indirect band-gap of about 2.1 eV. Moreover, lattice dynamic properties were calculated using density functional perturbation theory (DFPT) in order to assign the experimental Raman bands. In addition, we performed temperature-dependent Raman spectroscopic studies in the Bi2(MoO4)3 crystals to obtain information on structural changes induced by effects of the temperature change. From the changes observed in the Raman spectra phase transitions at ∼ 668 and 833 K were inferred, with the last one possibly related to the disorder due to the heating process.