Ab initio study of Z2 topological phases in perovskite (111) (SrTiO3)7/(SrIrO3)2 and (KTaO3)7/(KPtO3)2 multilayers
Abstract
Honeycomb structures formed by the growth of perovskite 5d transition metal oxide heteroestructures along the (111) direction in t2g5 configuration can give rise to topological ground states characterized by a topological index =1. Using a combination of a tight binding model and ab initio calculations we study the multilayers (SrTiO3)7/(SrIrO3)2 and (KTaO3)7/(KPtO3)2 as a function of parity asymmetry, on-site interaction and uniaxial strain and determine the nature and evolution of the gap. (SrTiO3)7/(SrIrO3)2 is found to be a topological semimetal. (KTaO3)7/(KPtO3)2 is a topological Mott insulator that can be driven to a trivial insulating phase by an external electric field.
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