Pressure-induced structural changes in α-MoO3 probed by X-ray absorption spectroscopy

Inga Jonane,Alexei Kuzmin,Francois Baudelet,Lucie Nataf,Tetsuo Irifune,Andris Anspoks

doi:10.1088/1757-899x/503/1/012018

Abstract

Energy-dispersive X-ray absorption spectroscopy at the Mo K-edge was used to study pressure-induced (up to 36 GPa) changes in the local atomic structure of 2D layered oxide α-MoO3. A linear combination analysis based on the low and high-pressure X-ray absorption near edge structure (XANES) spectra shows clear evidence of two high-pressure phases, existing at 18-25 GPa and above 32 GPa. The first transition is due to gradual decrease of the interlayer gap, whereas the second one – to its collapse and oxide structure reconstruction. The local atomic structure around molybdenum atoms at 0.2, 18.5 and 35.6 GPa was determined from the extended X-ray absorption fine structure (EXAFS) using reverse Monte Carlo calculations.

Highlights

After the discovery of graphene, other members of 2D layered materials family, including molybdenum trioxide (MoO3), have been intensively investigated due to their unique properties [1]
We report on the pressure-dependent X-ray absorption spectroscopy (XAS) study of α-MoO3 up to ∼36 GPa to evaluate the influence of pressure on the local atomic and electronic structure
A phase fraction was evaluated from X-ray absorption near edge structure (XANES) in the energy range from 19985 to 20075 eV at each pressure using a linear combination analysis (LCA)

Summary

Introduction

After the discovery of graphene, other members of 2D layered materials family, including molybdenum trioxide (MoO3), have been intensively investigated due to their unique properties [1]. Energy-dispersive X-ray absorption spectroscopy at the Mo K-edge was used to study pressure-induced (up to 36 GPa) changes in the local atomic structure of 2D layered oxide α-MoO3. A linear combination analysis based on the low and high-pressure X-ray absorption near edge structure (XANES) spectra shows clear evidence of two high-pressure phases, existing at 18-25 GPa and above 32 GPa. The first transition is due to gradual decrease of the interlayer gap, whereas the second one – to its collapse and oxide structure reconstruction.

Results

Conclusion