First-principles calculations of the structural, elastic and electronic properties of MNxC1-x (M=Ti, Zr, Hf; 0<x<1) carbonitrides at ambient and elevated hydrostatic pressure

TL;DR

This study uses first-principles calculations to analyze how the structural, electronic, and elastic properties of transition metal carbonitrides vary with nitrogen content and pressure, revealing linear property dependencies and bond ionicity changes.

Contribution

It provides a comprehensive first-principles analysis of MNxC1-x carbonitrides, highlighting linear property trends and bond ionicity evolution with nitrogen substitution and pressure.

Findings

Lattice constants, densities, and bulk moduli vary linearly with nitrogen concentration.

Bond ionicity increases as carbon is replaced by nitrogen.

Properties can be estimated for any x between 0 and 1.

Abstract

The structural, electronic, and elastic properties of three mixed transition metal carbonitrides TiNxC1-x, ZrNxC1-x, and HfNxC1-x (0<x<1) with the rock-salt structure were calculated at ambient and elevated up to 50 GPa hydrostatic pressures in the framework of the density functional theory methods. The lattice constants, densities, and bulk moduli of the considered compounds were shown to behave as linear functions of the nitrogen concentration x. The obtained linear dependencies of all these parameters allow for getting their estimates at any value of x in the range from 0 to 1. Gradual enhancement of the ionicity of the chemical bonds with gradual replacement of carbon by nitrogen was demonstrated by calculating the bond orders and electron density difference distributions.