Orbital Control of Noncollinear Magnetic Order in Nickel Oxide Heterostructures

Abstract

We have used resonant x-ray diffraction to develop a detailed description of antiferromagnetic ordering in epitaxial superlattices based on two-unit-cell thick layers of the strongly correlated metal LaNiO3. We also report reference experiments on thin films of PrNiO3 and NdNiO3. The resulting data indicate a spiral state whose polarization plane can be controlled by adjusting the Ni d-orbital occupation via two independent mechanisms: epitaxial strain and spatial confinement of the valence electrons. The data are discussed in light of recent theoretical predictions.

Confinement-driven transitions between topological and Mott phases in(LaNiO3)N/(LaAlDoennig1, Pickett2, Pentcheva3 2014Phys. Rev. B676870View full textAdd to dashboardCite

“…Instead, DFT studies on (001) SLs indicate that both e g states contribute to the Fermi surface [9][10][11] . Nevertheless, these (001) SLs have proven to be a fruitful playground to explore lowdimensional phenomena such as a MIT due to confinement and Coulomb interaction [11][12][13][14][15][16] . The possibility of topologically nontrivial behavior is currently shifting the interest from the much studied (001) stacking of AO/BO 2 planes to the (111)-perovskite superlattices with a B/AO 3 sequence.…”

Orbital polarization in strainedLaNiO3: Structural distortions and correlation effects

“…16,17 It was also demonstrated that both strain and dimensional confinement can drive an LNO film towards a spin-density-wave state, which is similar to what is observed in the insulating phase of other nickelates. 18 This makes LaNiO 3 a very suitable system for materials design by strain engineering and heterostructuring.…”

Experimental verification of orbital engineering at the atomic scale: Charge transfer and symmetry breaking in nickelate heterostructures

“…directly correlates to the material's resulting properties. [1][2][3][4][5] For example, systems such as the manganites (colossal magnetoresistance), 6 the cobaltates (spin-state transitions), 7,8 and the cuprates (hightemperature superconductivity) 9,10 owe their behaviors to specific configurations of the electronically active transition-metal cation d orbitals, which, for near-cubic symmetry, are split into the (lower energy) t 2g and (higher energy) e g orbitals. The development of atomically precise growth techniques for oxides has opened up the possibility of controlling orbital configurations via layered heterostructures.…”