Abstract
Motivated by recent reports of superconductivity in Sr-doped films on (001) [Nature (London) 572, 624 (2019)], we explore the role of the polar interface on the structural and electronic properties of (001) () by performing first-principles calculations including a Coulomb repulsion term. For infinite-layer nickelate films (), electronic reconstruction drives the surprising emergence of a two-dimensional electron gas (2DEG) at the interface involving a strong occupation of the Ti states. This effect is more pronounced than in (001) and accompanied by a substantial reconstruction of the Fermi surface: a depletion of the self-doping Nd states and an enhanced Ni orbital polarization reaching up to at the surface, reflecting a single hole in the states, i.e., cupratelike behavior. In contrast, no 2DEG forms for perovskite films () or if a single perovskite layer persists at the interface. We show that the topotactic reaction from the perovskite to the infinite-layer phase is confined to the nickelate film, whereas the substrate remains intact.
- Received 10 January 2020
- Revised 7 April 2020
- Accepted 15 June 2020
DOI:https://doi.org/10.1103/PhysRevB.102.020502
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