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arXiv · 1501.01902

SmO thin films: a flexible route to correlated flat bands with nontrivial topology

Deepa Kasinathan·Klaus Koepernik·L. H. Tjeng·Maurits W. Haverkort
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Abstract

Using density functional theory based calculations, we show that the correlated mixed-valent compound SmO is a 3D strongly topological semi-metal as a result of a 4$f$-5$d$ band inversion at the X point. The [001] surface Bloch spectral density reveals two weakly interacting Dirac cones that are quasi-degenerate at the M_bar-point and another single Dirac cone at the Gamma_bar-point. We also show that the topological non-triviality in SmO is very robust and prevails for a wide range of lattice parameters, making it an ideal candidate to investigate topological nontrivial correlated flat bands in thin-film form. Moreover, the electron filling is tunable by strain. In addition, we find conditions for which the inversion is of the 4f-6s type, making SmO to be a rather unique system. The similarities of the crystal symmetry and the lattice constant of SmO to the well studied ferromagnetic semiconductor EuO, makes SmO/EuO thin film interfaces an excellent contender towards realizing the quantum anomalous Hall effect in a strongly correlated electron system.

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Deepa Kasinathan, Klaus Koepernik, L. H. Tjeng, Maurits W. Haverkort. 2015-01-08. SmO thin films: a flexible route to correlated flat bands with nontrivial topology. https://doi.org/10.1103/physrevb.91.195127

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