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TT: Fachverband Tiefe Temperaturen

TT 8: Low-Dimensional Systems: Oxide Hetero-Interfaces

TT 8.6: Vortrag

Montag, 16. März 2015, 10:45–11:00, H 3010

Effect of band filling and symmetry breaking on the electronic ground state in (LaXO₃)₂/(LaAlO₃)₄(111) (X=3d) superlattices — •David Doennig¹, Warren E. Pickett², and Rossitza Pentcheva^3,1 — ¹Forschungs-Neutronenquelle (FRMII), TU München — ²University of California Davis, U.S.A. — ³Faculty of Physics, University of Duisburg-Essen, Lotharstr. 1, 47048 Duisburg, Germany

Structural patterns, e.g. a buckled honeycomb lattice, realized in (111)-oriented perovskite bilayers may lead to exotic electronic ground states such as a Dirac-point Fermi surface [1-3]. Based on density functional theory calculations including a Hubbard U term, we explore systematically the effect of band filling in [111]-oriented (LaXO₃)₂/(LaAlO₃)₄ superlattices with X spanning the series of open shell 3d ions. The interplay of charge, spin, orbital, and lattice degrees of freedom reveals some regularities over the series, but also several unexpected symmetry lowering reconstructions that can guide the design of artificial materials with desired spin-charge-orbital order in conjunction with size of the energy gap and the possibility for emergent topological character. We acknowledge funding by the DFG (SFB/TR80, project G3).

[1] D. Xiao et al., Nat. Commun. 2, 596 (2011).

[2] D. Doennig, W. E. Pickett, and R. Pentcheva,

Phys. Rev. Lett. 111, 126804 (2013).

[3] D. Doennig, W. E. Pickett, and R. Pentcheva,

Phys. Rev. B 89, 121110(R) (2014).