Modifying the Electronic Orbitals of Nickelate Heterostructures Via Structural Distortions

TL;DR

This paper presents a materials design strategy to induce large orbital polarization in nickelate heterostructures, creating a single-band electronic surface similar to cuprate superconductors, using structural distortions and superlattices.

Contribution

The study introduces a general approach combining atomic-scale distortions and tri-component superlattices to engineer orbital polarization in nickelates, verified by ab initio calculations and experiments.

Findings

Achieved large orbital energy splittings in nickelate heterostructures.

Created a two-dimensional single-band electronic surface at the Fermi energy.

Experimental verification of the structural motifs enabling the design.

Abstract

We describe a general materials design approach that produces large orbital energy splittings (orbital polarization) in nickelate heterostructures, creating a two-dimensional single-band electronic surface at the Fermi energy. The resulting electronic structure mimics that of the high temperature cuprate superconductors. The two key ingredients are: (i) the construction of atomic-scale distortions about the Ni site via charge transfer and internal electric fields, and (ii) the use of three component (tri-component) superlattices to break inversion symmetry. We use {\it ab initio} calculations to implement the approach, with experimental verification of the critical structural motif that enables the design to succeed.