# Electronic Structure, Lattice Dynamics, and Pressure-Induced Phase Transitions in Gd2MoO6: A Combined Theoretical and Experimental Study

## TL;DR

This paper studies the electronic and structural properties of Gd2MoO6 under pressure, revealing its semiconducting nature and phase transitions at specific pressures.

## Contribution

The novel contribution is the identification of two pressure-induced phase transitions in Gd2MoO6 using combined theoretical and experimental methods.

## Key findings

- Gd2MoO6 is a semiconductor with an indirect band gap of approximately 1.92 eV.
- Two phase transitions occur at pressures of 3.1–3.3 GPa and 9.5–10 GPa.
- The material's structure is governed by hybrid ionic-covalent bonding.

## Abstract

This study presents a combined theoretical and experimental
investigation
into the structural, electronic, and vibrational properties of Gd2MoO6. To gain deeper insight into its chemical
composition, first-principles calculations were employed, emphasizing
energy band analysis. The conduction band minimum is positioned at
the high-symmetry Γ-point, while the valence band maximum appears
between the Z and Γ-points. These results indicate that Gd2MoO6 is a semiconductor exhibiting an indirect
band gap of approximately 1.92 eV. Furthermore, lattice dynamics were
examined using density functional theory (DFT) to interpret the experimental
Raman and infrared spectra. Hirshfeld surface and structural analyses
reveal that Gd2MoO6 exhibits a hybrid ionic-covalent
framework governed by dominant Gd–O/Gd–O and Mo–O/O–Mo
bonds. Additionally, pressure-dependent Raman spectroscopy was carried
out to explore structural modifications resulting from pressure variations.
Based on the spectral changes, two phases’ transitions were
identified at approximately 3.1–3.3 GPa and 9.5–10 GPa,
potentially linked to increased disorder of octahedra induced by pressure
effects. The principal component analysis and hierarchical cluster
analysis identified two phase transitions at near pressure range of
3.1–3.3 GPa and 9.5–10. GPa, which are in agreement
with the pressure-dependent Raman studies.