Abstract
We report a study of the high-pressure behavior of the structural and electronic properties of Zn2V2O7 by means of first-principle calculations using the CRYSTAL code. Three different approaches have been used, finding that the Becke–Lee–Yang–Parr functional is the one that best describes Zn2V2O7. The reported calculations contribute to the understanding of previous published experiments. They support the existence of three phase transitions for pressures smaller than 6 GPa. The crystal structure of the different high-pressure phases is reported. We have also made a systematic study of the electronic band-structure, determining the band-gap and its pressure dependence for the different polymorphs. The reported results are compared to previous experimental studies. All the polymorphs of Zn2V2O7 have been found to have a wide band gap, with band-gap energies in the near-ultraviolet region of the electromagnetic spectrum.
Highlights
Zinc pyrovanadate (Zn2V2O7) and related compounds are receiving a great deal of attention because of the multiple practical applications of these compounds
We found that the B3LYP functional is the one that best describe the crystal structure of Zn2V2O7 at ambient conditions
From the calculated partial electronic density of states (DOS) we have found that the states at the top of the valence band (VB) are dominated by O 2p orbitals, while the states near the bottom of the conduction band (CB) are dominated by V 3d orbitals, which are partially hybridized with O 2p orbitals
Summary
Zinc pyrovanadate (Zn2V2O7) and related compounds are receiving a great deal of attention because of the multiple practical applications of these compounds. 7) and subsequent transitions take place at 3.8 GPa) (to a triclinic polymorphs named as g-phase) and 10.8 GPa (post-g-phase).[7] For two of the high-pressure (HP) polymorphs (b and g) a crystal structure has been proposed from previous X-ray diffraction studies; the crystal structures have not been properly solved.[7] The proposed structures involve large changes in the unit-cell volume and a modi cation of the coordination polyhedra They are expected to affect other physical properties, in particular, the electronic band gap.[8] the in uence of high-pressure on the electronic properties of Zn2V2O7 has not been studied yet. The band-structure calculations here reported support that Zn2V2O7 is a wide band-gap material, clarifying discrepancies found in the literature with values for band-gap energy (Eg) going from 2.5 to 3.5 eV.[2,13,14,15,16]
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