Uniaxial strain-modulated conductivity in manganite superlattice (LaMnO₃/SrMnO₃)

Abstract

We have investigated the magnetic ordering and electrical conductivity transitions of (LaMnO₃)₂/(SrMnO₃)₂ superlattices grown on SrTiO₃ substrate based on density-functional theory. It is found that the uniaxial tensile strain along the z axis of about 1.4% induced a magnetic transition from antiferromagnetic to ferromagnetic ordering. At the interface the orbital order changes from a combination of x²−y² and 3z²−r² to x²−y² as strain becomes more compressive; as a result the electrical transport is transformed from three-dimensions to two-dimensions at the high uniaxial compressive strain. Our results suggest that the out-of-plane electrical conductivity can be modulated and controlled by uniaxial strain.