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

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.

Paper+supplement

References in corpus (9)

• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Insulators with Inversion Symmetry
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• First direct observation of Spin-textures in Topological Insulators : Spin-resolved ARPES as a probe of topological quantum spin Hall effect and Berry's phase
• Electrically detected interferometry of Majorana fermions in a topological insulator
• On the $Z_2$ classification of Quantum Spin Hall Models
• Chern insulators from heavy atoms on magnetic substrates
• Epitaxial and layer-by-layer growth of EuO thin films on yttria-stabilized cubic zirconia (001) using MBE distillation

Cited by in corpus (5)

• Coexistence of Weyl semimetal and Weyl nodal loop semimetal phases in a collinear antiferromagnet
• Z${}_2$ nontrivial topology of rare-earth binary oxide superconductor
• Hard and soft x-ray photoemission spectroscopy study of the new Kondo system SmO thin film
• Rocksalt rare-earth monoxides as electronic and magnetic materials
• Anomalous 4$f$ fine structure in TmSe${}_{1-x}$Te${}_x$ across the metal-insulator transition