Elastic and Piezoresistive Properties of Nickel Carbides from First-Principles

TL;DR

This study uses first-principles calculations to explore the elastic and piezoresistive properties of nickel carbides, revealing their potential in mechanical sensing due to stable electronic properties under strain.

Contribution

It provides detailed first-principles insights into the elastic and electronic response of nickel carbides, a relatively unexplored area with implications for sensor applications.

Findings

Electronic density of states remains stable under strain.

Conductivity of Ni3C can change by up to 10% under mechanical stress.

Nickel carbides exhibit potential for mechanical sensing applications.

Abstract

The nickel--carbon system has received increased attention over the past years due to the relevance of nickel as a catalyst for carbon nanotube and graphene growth, where Nickel carbide intermediates may be involved or carbide interface layers form in the end. Nickel--carbon composite thin films comprising Ni$_3$C are especially interesting in mechanical sensing applications. Due to the meta-stability of nickel carbides, formation conditions and the coupling between mechanical and electrical properties are not yet well understood. Using first-principles electronic structure methods, we calculated the elastic properties of Ni$_3$C, Ni$_2$C and NiC, as well as changes in electronic properties under mechanical strain. We observe that the electronic density of states around the Fermi level does not change under the considered strains of up to 1%, which correspond to stresses up to 3GPa. Relative changes in conductivity of Ni$_3$C range up to maximum values of about 10%.