Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 59: Complex Oxides Interfaces and Charge Order

TT 59.4: Vortrag

Donnerstag, 4. April 2019, 15:45–16:00, H22

Magnetism and pseudo gap physics in SrVO₃ | SrTiO₃ heterostructures — •Matthias Pickem, Jan M. Tomczak, and Karsten Held — Institute of Solid State Physics, TU Wien, Austria

Modern atomic layer-by-layer deposition techniques allow for the study of materials in restricted geometries. Resulting effects of quantum confinement, e.g., in ultra-thin films are expected to be particularly pronounced for systems with strong electronic correlations. Indeed, the conventional Fermi-liquid state of bulk SrVO₃ was recently discovered to be destroyed in films below a critical thickness.

On the basis of these result we perform state-of-the-art density functional theory (DFT) + dynamical mean-field theory (DMFT) calculations. We first compute susceptibilities within DMFT and find antiferromagnetic ordering in the undoped cases and evidence of competing phases when doping, opening perspectives for oxide-based spin-tronic devices.

In order to properly describe possible non-local correlation effects stemming from the reduced dimensionality and the (potential) proximity of long-range ordered phases, we additionally apply the dynamical vertex approximation — a promising method beyond DMFT — that was recently extended to realistic materials calculations. Preliminary results suggest the presence of pseudo-gap physics, vaguely reminiscent of cuprate superconductors. The encountered large self-energy corrections to the local (DMFT) descriptors advocate for further studies of thin films and heterostructure in both theory and experiment.