High-pressure study of barium metavanadate monohydrate

Area of Science:

• Materials Science
• Solid State Physics
• Crystallography

Background:

• Barium metavanadate monohydrate (BaV2O6·H2O) is a vanadate compound with potential applications in materials science.
• Understanding its behavior under pressure is crucial for predicting its stability and properties in extreme environments.

Purpose of the Study:

• To investigate the high-pressure structural and electronic properties of barium metavanadate monohydrate.
• To compare its pressure response with anhydrous barium metavanadate.

Main Methods:

• Single-crystal X-ray diffraction up to 7.1 GPa.
• High-pressure optical absorption spectroscopy up to 10.1 GPa.
• Density-functional theory (DFT) calculations.

Main Results:

• BaV2O6·H2O crystallizes in an orthorhombic structure (P212121) that remains stable up to 8 GPa, unlike anhydrous BaV2O6.
• The crystal exhibits anisotropic compression, with the b-axis showing minimal compressibility.
• An indirect band gap decreases from 4.62(5) eV to 4.48(5) eV with increasing pressure.
• DFT calculations confirm experimental findings and attribute the band gap reduction to enhanced O 2p and V 3d hybridization.

Conclusions:

• BaV2O6·H2O demonstrates significant structural stability under high pressure.
• The observed decrease in band gap is pressure-induced and linked to electronic structure changes.
• With a bulk modulus of 33.0(5) GPa, it is among the more compressible vanadates.