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TT: Fachverband Tiefe Temperaturen
TT 94: Low-Dimensional Systems: Oxide Hetero-Interfaces
TT 94.8: Vortrag
Donnerstag, 3. April 2014, 17:00–17:15, HSZ 204
Confinement-driven electronic phases in
(LaAlO3)M/(LaNiO3)N(111) superlattices — •David Doennig and Rossitza Pentcheva — Ludwig-Maximilians University Munich
Complex oxide heterostructures exhibit a broad variability of functional properties and electronic states, not available in the bulk. Beyond the much studied (001)-oriented systems, here we highlight theoretical results on (111) perovskite superlattices (SLs) containing the correlated metal LaNiO3 (LNO) and the band insulator LaAlO3 (LAO). Density functional theory calculations with an on-site Coulomb repulsion term reveal a rich spectrum of electronic phases in (LAO)M/(LNO)N(111) SLs as a function of the LNO and LAO thickness N and M in the superlattice. In the double perovskite 1/1 system, a Jahn-Teller distortion with dz2 orbital polarization leads to a ferromagnetic Mott insulating phase, so far unanticipated for nickelates. For the LNO bilayer (N=2) with graphene topology, a Dirac-point Fermi surface is obtained, while symmetry breaking leads to band gap opening with two inequivalent interfaces. For N≥ 3 the confined LNO slab undergoes a metal-to-insulator transition to a half-semimetallic phase with conduction originating from the interfaces. Antiferromagnetic arrangements allow combining motifs of the bilayer and single trigonal layer band structures in engineered artificial mixed phases. We acknowledge funding by the DFG, SFB/TR80.