Potential super-hard Osmium di-nitride with fluorite structure: First-principles calculations

TL;DR

This study uses first-principles calculations to explore the stability and properties of osmium and platinum compounds with fluorite structures, identifying OsN₂ as a super-hard, metallic phase with high bulk modulus.

Contribution

It is the first to systematically analyze the mechanical stability and electronic properties of these compounds, revealing OsN₂ as a potentially super-hard material.

Findings

OsN₂ is mechanically stable with a bulk modulus of 360.7 GPa.

OsN₂ exhibits metallic behavior based on band structure analysis.

Only PtN₂, OsN₂, and OsO₂ are mechanically stable among studied compounds.

Abstract

We have performed systematic first-principles calculations on di-carbide, -nitride, -oxide and -boride of platinum and osmium with the fluorite structure. It is found that only PtN$_{2}$, OsN$_{2}$ and OsO$_{2}$ are mechanically stable. In particular OsN$_{2}$ has the highest bulk modulus of 360.7 GPa. Both the band structure and density of states show that the new phase of OsN$_{2}$ is metallic. The high bulk modulus is owing to the strong covalent bonding between Os 5\textit{d} and N 2\textit{p} states and the dense packed fluorite structure.