High-pressure formation and stabilization of binary iridium hydrides

Area of Science:

• Materials Science
• Solid-State Chemistry
• Computational Physics

Background:

• Iridium hydrides are not well-characterized, especially under extreme pressure conditions.
• Understanding the phase diagrams of transition metal hydrides is crucial for materials discovery.

Purpose of the Study:

• To investigate the stability and properties of binary iridium hydrides (IrxHy) under high pressure.
• To predict new stable phases of iridium hydrides using first-principles calculations.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to study IrxHy.
• The investigation covered a pressure range from 1 atm to 125 GPa.

Main Results:

• New iridium hydride phases, including a dihydride (Ibam, Z=2) and a trihydride (P63mc, Z=2), were predicted to stabilize at approximately 14 GPa and 5 GPa, respectively.
• Both dihydride and trihydride phases exhibit short, covalent-like interactions between iridium and hydrogen atoms.
• All investigated iridium hydrides displayed metallic characteristics, except for IrH3 (P63mc, Z=2) which showed a non-zero band gap and molecular behavior at intermediate pressures.

Conclusions:

• The study identifies novel stable phases of iridium hydrides under pressure.
• The unique electronic and structural properties of IrH3 suggest potential for further research into its applications.