High pressure structural, electronic, and optical properties of polymorphic InVO4 phases

TL;DR

This study uses density functional theory to analyze the structural, electronic, and optical properties of polymorphic InVO4 phases under high pressure, revealing phase transformation, electronic band gap changes, and optical property variations.

Contribution

It provides a detailed theoretical analysis of InVO4's phase transition, electronic structure, and optical properties under high pressure, which was not comprehensively reported before.

Findings

Orthorhombic to monoclinic phase transition at 5.6 GPa with 16.6% volume collapse

Band gap reduction from 4.02 eV to 1.67 eV under pressure

High-pressure phase shows potential for photocatalytic applications

Abstract

In the present work, we report a detailed density functional theory calculation on polymorphic InVO$_4$ phases by means of projector augmented wave method. The computed first-order structural phase transformation from orthorhombic \emph{(Cmcm)} to monoclinic \emph{(P2/c)} structure is found to occur around 5.6 GPa along with a large volume collapse of 16.6$\%$, which is consistent with previously reported experimental data. This transformation also leads to an increase in the coordination number of vanadium atom from 4 to 6. The computed equilibrium and high pressure structural properties of both InVO$_4$ phases, including unit cell parameters, equation of state, and bulk moduli, are in good agreement with the available experimental data. In addition, compressibility is found to be highly anisotropic and the \emph{b}-axis being more compressible than the other for both the structures. Electronic band structures for both the phases were calculated, and the band gap for orthorhombic and monoclinic InVO$_4$ are found to be 4.02 and 1.67 eV, respectively, within the Tran-Blaha Modified Becke-Johnson potential as implemented in linearized augmented planewave method. We further examined the optical properties such as dielectric function, refractive index, and absorption spectra for both the structures. From the implications of these results, it can be proposed that the high pressure InVO$_4$ phase can be more useful than orthorhombic phase for photo catalytic applications.