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arXiv · 1501.04602

Triangular Spin-Orbit-Coupled Lattice with Strong Coulomb Correlations: Sn Atoms on a SiC(0001) Substrate

Stefan Glass·Gang Li·Florian Adler·Julian Aulbach·Andrzej Fleszar·Ronny Thomale·Werner Hanke·Ralph Claessen·Jörg Schäfer
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Abstract

Two-dimensional (2D) atom lattices provide model setups for Coulomb correlations inducing competing ground states, partly with topological character. Hexagonal SiC(0001) is an intriguing wide-gap substrate, spectroscopically separated from the overlayer and hence reduced screening. We report the first study of an artificial high-Z atom lattice on SiC(0001) by Sn adatoms, based on combined experimental realization and theoretical modeling. Density-functional theory of our $\sqrt{3}$-structure model closely reproduces the scanning tunneling microscopy. Instead of metallic behavior, photoemission data show a deeply gapped state (~2 eV gap). Based on our calculations including dynamic mean-field theory, we argue that this reflects a pronounced Mott insulating scenario. We also find indications that the system is susceptible to antiferromagnetic superstructures. Such spin-orbit-coupled correlated heavy atom lattices on SiC(0001) thus form a novel testbed for peculiar quantum states of matter, with potential bearing for spin liquids and topological Mott insulators.

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Stefan Glass, Gang Li, Florian Adler, Julian Aulbach, Andrzej Fleszar, Ronny Thomale, Werner Hanke, Ralph Claessen, Jörg Schäfer. 2015-01-19. Triangular Spin-Orbit-Coupled Lattice with Strong Coulomb Correlations: Sn Atoms on a SiC(0001) Substrate. https://doi.org/10.1103/physrevlett.114.247602

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