Electronic and structural properties of crystalline and amorphous (TaNbHfTiZr)C from first principles

TL;DR

This study uses density functional theory to compare the electronic and structural properties of crystalline and amorphous (TaNbHfTiZr)C high entropy carbide, revealing differences in volume, bulk modulus, and electronic contributions.

Contribution

First-principles DFT analysis of both phases of (TaNbHfTiZr)C provides insights into their structural and electronic differences, confirming supercell adequacy for complex HEMs.

Findings

Amorphous phase has larger lattice volume and lower bulk modulus.

Both phases exhibit metallic behavior with similar transition metal contributions.

Supercells of 2x2x2 are sufficient for reliable property simulation.

Abstract

High entropy materials (HEMs) are of great interest for their mechanical, chemical and electronic properties. In this paper we analyse (TaNbHfTiZr)C, a carbide type of HEM, both in crystalline and amorphous phases, using density functional theory (DFT). We find that the relaxed lattice volume of the amorphous phase is larger, while its bulk modulus is lower, than that of its crystalline counterpart. Both phases are metallic with all the transition metals contributing similarly to the density of states (DOS) close to the Fermi level, with Ti and Nb giving the proportionally largest contribution of states. We confirm that despite its great structural complexity, 2x2x2 supercells are large enough for reliable simulation of the presented mechanical and electronic properties by DFT.