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arXiv · 1401.6105

Electron correlation and magnetism at the LaAlO$_3$/SrTiO$_3$ interface: A DFT+DMFT investigation

Frank Lechermann·Lewin Boehnke·Daniel Grieger·Christoph Piefke
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Abstract

We shed light on the interplay between structure and many-body effects relevant for itinerant ferromagnetism in LaAlO$_3$/SrTiO$_3$ 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. Though many-body behavior is also active in the defect-free interface, a ferromagnetic instability occurs only with oxygen vacancies. A minimal Ti two-orbital $e_g$-$t_{2g}$ description for the correlated subspace is derived. Magnetic order affected by quantum fluctuations builds up from effective double exchange between nearly-localized $e_g$ and mobile $xy$ electrons.

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Frank Lechermann, Lewin Boehnke, Daniel Grieger, Christoph Piefke. 2014-08-26. Electron correlation and magnetism at the LaAlO$_3$/SrTiO$_3$ interface: A DFT+DMFT investigation. https://doi.org/10.1103/physrevb.90.085125

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