Charge transfer and metallicity in LaNiO3/LaMnO3 superlattices

Alejandro Lopez-Bezanilla1 , ∗ Louis-Fran¸cois Arsenault2 , Anand Bhattacharya1 , Peter B. Littlewood1 3, and Andrew J. Millis2

1Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA

2Department of Physics, Columbia University, New York, New York 10027, USA

and

3 James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States

Abstract:

Motivated by recent experiments, we use the +U extension of the generalized gradient approximation to density functional theory to study superlattices composed of alternating layers of LaNiO3 and LaMnO3. For comparison we also study a rocksalt ((111) double perovskite) structure and bulk LaNiO3 and LaMnO3. A Wannier function analysis indicates that band parameters are transferable from bulk to superlattice situations with the exception of the transition metal d-level energy, which has a contribution from the change in d-shell occupancy. The charge transfer from Mn to Ni is found to be moderate in the superlattice, indicating metallic behavior, in contrast to the insulating behavior found in recent experiments, while the rocksalt structure is found to be insulating with a large Mn-Ni charge transfer. We suggest a high density of cation antisite defects may account for the insulating behavior experimentally observed in short-period superlattices.

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https://arxiv.org/pdf/1704.08886.pdf