Temperature dependence Raman spectroscopy and DFT calculations of Bi 2 (MoO 4 ) 3 .

This work reports a theoretical and experimental study on the electronic and vibrational properties of Bi ₂ (MoO ₄ ) 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 Bi ₂ (MoO ₄ ) 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 Bi ₂ (MoO ₄ ) 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.
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