We propose three transition-metal adatom systems on 3C-SiC(111) surfaces as a versatile platform to realize massless Dirac fermions and flat bands with strong electronic correlations. Using density functional theory combined with the constrained random phase approximation and dynamical mean-field theory, we investigate the electronic properties of Ti, V, and Cr adatoms. The triangular surface lattices exhibit narrow bandwidths and effective two-band Hubbard models near the Fermi level, originating from partially filled, localized d-orbitals of the adatoms. Our study reveals a materials trend from a flat band Fermi liquid (Cr) via a paramagnetic Mott insulator with large local moments (V) to a Mott insulator on the verge to a heavy Dirac semimetal (Ti) showcasing the diverse nature of these strongly correlated systems. Specifically, the flat bands in the Cr and the well-defined Dirac cones in the strained metallic~Ti lattice indicate high potential for realizing topological and correlated phases.
@article{arxiv.2410.17165,
title = {Engineering correlated Dirac fermions and flat bands on SiC with transition-metal adatom lattices},
author = {Henri Menke and Niklas Enderlein and Yi-Ting Tseng and Michel Bockstedte and Janina Maultzsch and Giorgio Sangiovanni and Philipp Hansmann},
journal= {arXiv preprint arXiv:2410.17165},
year = {2024}
}