Ab initio study of nontrivial topological phases in corundum structured $($M${}_2$O${}_3)/($Al${}_2$O${}_3{)}_5$ multilayers

Abstract

\textit{Ab initio} calculations have been performed on hexagonal layers of M${}_2$O${}_3$ (M being several transition metals of the $5d$ series) sandwiched by a band insulator such as Al${}_2$O${}_3$ that provides the honeycomb lattice where the $5d$ electrons reside. This corundum-structure-based superlattice is the most obvious way to design a honeycomb lattice with transition metal cations avoiding the use of largely polar surfaces. We obtain that this system supports the presence of Dirac cones at the Fermi level that open up with the introduction of spin-orbit coupling at various fillings of the $5d$ band. The DFT calculations performed in this work show that the $5d^5$ situation is always a trivial insulator, whereas the $5d^8$ filling presents topological insulating configurations which evolve into a trivial state with increasing tensile strain or on-site Coulomb potential U. However, LDA+U calculations show a stable antiferromagnetic solution for the $5d^8$ case at every U value, which would break time reversal symmetry and could affect the topological properties of the system. We also discuss the similarities with the buckled honeycomb lattice obtained using perovskite (111) bilayers previously studied in literature, in particular for the $5d^5$ and $5d^8$ configurations. This work provides some clues on the stability of topological phases using metal oxides in general.

11 pages, 7 figures

References in corpus (16)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Topological Insulators with Inversion Symmetry
• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• Topological Crystalline Insulators
• Topological Mott Insulators
• Correlated Topological Insulators with Mixed Valence
• Direct Evidence for the Dirac-Cone Topological Surface States in Ternary Chalcogenide TlBiSe2
• Topological Surface States and Dirac point tuning in ternary Bi2Te2Se class of topological insulators
• Topological insulators and thermoelectric materials
• Interface Between Topological and Superconducting Qubits
• Characterization of a topological Mott insulator in one dimension
• Confinement-driven transitions between topological and Mott phases in (LaNiO3)${}_N$/(LaAlO3)${}_M$(111) superlattices
• Theoretical prediction of topological insulator in ternary rare earth chalcogenides
• Fabrication of (111)-oriented Ca0.5Sr0.5IrO3/SrTiO3 superlattices; a designed playground for honeycomb physics

Cited by in corpus (7)

• Transition-Metal Oxide (111) bilayers
• Geometrical lattice engineering of complex oxide heterostructures: a designer approach to emergent quantum states
• Quantum spin Hall effect in rutile-based oxide multilayers
• Confinement-driven electronic and topological phases in corundum-derived $3d$-oxide honeycomb lattices
• Band crossings in honeycomb-layered transition metal compounds
• Interaction-driven spin-orbit effects and Chern insulating phases in corundum-based $4d$ and $5d$ oxide honeycomb lattices
• Dirac topological insulator in the d${}_{z^2}$ manifold of a honeycomb oxide