Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 56: Frontiers of Electronic Structure Theory: Many-Body Effects on the Nano-Scale IV

O 56.12: Talk

Wednesday, March 18, 2015, 18:00–18:15, MA 004

Ferromagnetism from strongly correlated electrons at the LaAlO₃/SrTiO₃ interface — •Frank Lechermann, Lewin Boehnke, Malte Behrmann, Daniel Grieger, and Christoph Piefke — I. Institut für Theoretische Physik, Universität Hamburg

We shed light on the interplay between structure and many-body effects relevant for itinerant ferromagnetism in LaAlO₃/SrTiO₃ heterostructures. The realistic correlated electronic structure is studied by means of the (spin-polarized) charge self-consistent combination of density functional theory (DFT) with dynamical mean-field theory (DMFT) beyond the realm of static correlation effects [1]. A ferromagnetic instability occurs only with oxygen vacancies and it is possible to account for the basic mechanism by an derived minimal Ti two-orbital e_g−t_2g description for the correlated subspace. Magnetic order affected by quantum fluctuations with a Ti moment of 0.2µ_B builds up from effective double exchange, which can be traced to the dilute defect regime. [1] F. Lechermann, L. Boehnke, D. Grieger and C. Piefke, Phys. Rev. B 90, 085125 (2014)