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arXiv · 2410.17165

Engineering correlated Dirac fermions and flat bands on SiC with transition-metal adatom lattices

Henri Menke·Niklas Enderlein·Roland Gillen·Yi-Ting Tseng·Michel Bockstedte·Janina Maultzsch·Giorgio Sangiovanni·Philipp Hansmann
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Abstract

We propose three transition-metal adatom systems on SiC 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 adatom d orbitals. For the undoped systems our calculations reveal two distinct Mott insulating ground states. While the V lattice is a paramagnetic textbook case with large local moments, the Cr lattice, in contrast, is on the edge of a phase transition toward a flat-band Fermi liquid. The Ti lattice realizes a heavy Dirac semimetal at zero doping.

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Henri Menke, Niklas Enderlein, Roland Gillen, Yi-Ting Tseng, Michel Bockstedte, Janina Maultzsch, Giorgio Sangiovanni, Philipp Hansmann. 2024-10-22. Engineering correlated Dirac fermions and flat bands on SiC with transition-metal adatom lattices. https://doi.org/10.1103/yh3v-pwz9

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