Interface exchange processes in LaAlO${}_3$/SrTiO${}_3$ induced by oxygen vacancies

Abstract

Understanding the role of defects in oxide heterostructures is crucial for future materials control and functionalization. We hence study the impact of oxygen vacancies (OVs) at variable concentrations on orbital- and spin exchange in the LaAlO${}_3$/SrTiO${}_3$ interface by first principles many-body theory and real-space model-Hamiltonian techniques. Intricate interplay between Hubbard $U$ and Hund's coupling $J_{\mathrm{H}}$ for OV-induced correlated states is demonstrated. Orbital polarization towards an effective $e_g$ state with predominant local antiferromagnetic alignment on Ti sites near OVs is contrasted with $t_{2g}(xy)$ states with ferromagnetic tendencies in the defect-free regions. Different magnetic phases are identified, giving rise to distinct net-moment behavior at low and high OV concentrations. This provides a theoretical basis for prospective tailored magnetism by defect manipulation in oxide interfaces.

11 pages, 10 figures

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Cited by in corpus (11)

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• Electron dichotomy on the SrTiO${}_3$ defect surface augmented by many-body effects
• Electronic phase separation at LaAlO3/SrTiO3 interfaces tunable by oxygen deficiency
• Oxygen-vacancy driven electron localization and itinerancy in rutile-based TiO${}_2$
• Large effects of subtle electronic correlations on the energetics of vacancies in alpha-Fe
• Rigorous symmetry adaptation of multiorbital rotationally invariant slave-boson theory with application to Hund's rules physics
• Oxygen vacancies and hydrogen doping in LaAlO3/SrTiO3 heterostructures: electronic properties and impact on surface and interface reconstruction
• Spin-orbit and anisotropic strain effects on the electronic correlations of Sr${}_2$RuO${}_4$
• Spin-Orbit Interaction and Kondo Scattering at the PrAlO${}_3$/SrTiO${}_3$ Interface: Effects of Oxygen Content
• Versatile Approach to the Spin Dynamics in Correlated Electron Systems
• Oxide Heterostructures from a Realistic Many-Body Perspective