Ab-initio electronic and magnetic structure in La_0.66Sr_0.33MnO_3: strain and correlation effects

Abstract

The effects of tetragonal strain on electronic and magnetic properties of strontium-doped lanthanum manganite, La_{2/3}Sr_{1/3}MnO_3 (LSMO), are investigated by means of density-functional methods. As far as the structural properties are concerned, the comparison between theory and experiments for LSMO strained on the most commonly used substrates, shows an overall good agreement: the slight overestimate (at most of 1-1.5 %) for the equilibrium out-of-plane lattice constants points to possible defects in real samples. The inclusion of a Hubbard-like contribution on the Mn d states, according to the so-called "LSDA+U" approach, is rather ineffective from the structural point of view, but much more important from the electronic and magnetic point of view. In particular, full half-metallicity, which is missed within a bare density-functional approach, is recovered within LSDA+U, in agreement with experiments. Moreover, the half-metallic behavior, particularly relevant for spin-injection purposes, is independent on the chosen substrate and is achieved for all the considered in-plane lattice constants. More generally, strain effects are not seen to crucially affect the electronic structure: within the considered tetragonalization range, the minority gap is only slightly (i.e. by about 0.1-0.2 eV) affected by a tensile or compressive strain. Nevertheless, we show that the growth on a smaller in-plane lattice constant can stabilize the out-of-plane vs in-plane e_g orbital and significatively change their relative occupancy. Since e_g orbitals are key quantities for the double-exchange mechanism, strain effects are confirmed to be crucial for the resulting magnetic coupling.

arXiv comment16 pages, 7 figures, to be published on J. Phys.: Condensed Matter

References in corpus (8)

• Nearly total spin polarization in La2/3Sr1/3MnO3 from tunneling experiments
• Influence of strain and oxygen vacancies on the magnetoelectric properties of multiferroic bismuth ferrite
• Implementation of the LDA+U method using the full potential linearized augmented plane wave basis
• Spin-polarized tunneling spectroscopy in tunnel junctions with half-metallic electrodes
• Half-Metallicity of LSMO
• Effects of uniaxial strain in LaMnO_3
• Electronic and magnetic properties of the (001) surface of hole-doped manganites
• Local tetragonal distortion in La_{0.7}Sr_{0.3}MnO_3 strained thin films probed by x-ray absorption spectroscopy

Cited by in corpus (8)

• Electronic and Magnetic Structure of the (LaMnO${}_3$)${}_{2n}$/(SrMnO${}_3$)${}_n$ Superlattices
• Ferrodistortive instability at the (001) surface of half-metallic manganites
• Effect of strain on the orbital and magnetic ordering of manganite thin films and their interface with an insulator
• Momentum-resolved electronic structure at a buried interface from soft x-ray standing-wave angle-resolved photoemission
• Conditions for the growth of smooth La0.7Sr0.3MnO3 thin films by pulsed electron ablation
• Striping of orbital-order with charge-disorder in optimally doped manganites
• Surface antiferromagnetism and incipient metal-insulator transition in strained manganite films
• Noncentrosymmetric structural transitions in ultrashort ferroelectric AGaO${}_3$/A'GaO${}_3$ superlattices