Electronic structure and magnetism in two-dimensional hexagonal 5d transition metal carbides, Tan+1Cn (n=1,2,3)

TL;DR

This study uses density functional theory to explore the electronic and magnetic properties of two-dimensional hexagonal tantalum carbides, revealing the dominance of Ta 5d states, weak correlations, and the influence of spin-orbit interactions.

Contribution

It provides new insights into the electronic structure, magnetic tendencies, and spin-orbit effects in 2D tantalum carbides with different layer numbers, which were previously unexplored.

Findings

Ta 5d states dominate the electronic structure

Carbide sheets are prone to magnetic order

Spin orbit interactions significantly affect n=2

Abstract

Density functional calculations are used to investigate the electronic structure of two-dimensional 5d tantalum carbides with honeycomb-like lattice structures. We focus on changes in the low-energy bands near the Fermi level with dimensionality. We find that the Ta 5d states dominate, but the extended nature of the wavefunctions makes them weakly correlated. The carbide sheets are prone to long range magnetic order. We evaluate the stability of these states to enhanced electron--electron interactions through a Hubbard U correction. Lastly, we find spin orbit interactions strongly renormalize the band structure for n=2, but play a minor role in n=1 and 3.