Influence of high pressure on structural, electronic and mechanical properties of tetragonal FeH5

First-principles method is performed to investigate the structural, electronic, and mechanical characteristics of the tetragonal I/4mmm-FeH5 in the pressure range from 100GPa to 300 GPa. At 130 GPa and 150 GPa, the lattice parameters of I/4mmm-FeH5 are matched well with available values. The pressure has a more significant influence on the (c) over right arrow direction than the (a) over right arrow and (b) over right arrow direction. Electronic calculations predicted that the I4/mmm-FeH5 has weak metallic behaviors and the ionic bond between Fe and H atom under pressure. The obtained elastic constants reveal the I/4mmm-FeH5 is mechanically stable between 100 GPa and 300 GPa. The bulk, shear, and Young's modulus are evaluated by Voigt-Reuss-Hill approximation. All these polycrystalline elastic moduli exhibit a monotonic feature as a function of pressure. The Poisson's ratio, Pugh's criterion, and Cauchy pressure indicate that the I4/mmm-FeH5 is ductile against pressure. Mechanical anisotropy is evaluated through several physical parameters. Finally, the Debye temperature estimated from the average wave velocity is found to monotonically increase with pressure.

Automated summary

The study reveals that I/4mmm-FeH5 exhibits good mechanical stability between 100 GPa and 300 GPa, with metallic properties and ionic bond formation under pressure. The elastic moduli show a monotonic increase with pressure.