Honeycomb structures formed by the growth of perovskite 5d transition metal oxide heterostructures along the (111) direction in a t2g5 configuration can give rise to topological ground states characterized by a topological index ν=1, as reported by Xiao. Using a combination of a tight binding model and ab initio calculations we study the multilayers (SrTiO3)7/(SrIrO 3)2 and (KTaO3)7/(KPtO3)2 as a function of parity asymmetry, on-site interaction U, and uniaxial strain and determine the nature and evolution of the gap. According to our density functional theory calculations, (SrTiO3)7/(SrIrO3)2 is found to be a topological semimetal whereas (KTaO3)7/(KPtO 3)2 is found to present a topological insulating phase that can be understood as the high U limit of the previous one, that can be driven to a trivial insulating phase by a perpendicular external electric field.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 18 Oct 2013|
|MoE publication type||A1 Journal article-refereed|