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Orbital reconstruction in nonpolar tetravalent transition-metal oxide layers.

Bogdanov NA, Katukuri VM, Romhányi J, Yushankhai V, Kataev V, Büchner B, van den Brink J, Hozoi L - Nat Commun (2015)

Bottom Line: We resolve in this regard the d-level structure of layered Sr2IrO4 by electron spin resonance.This implies that the iridium d levels are inverted with respect to their normal ordering.State-of-the-art electronic-structure calculations confirm the level switching in Sr2IrO4, whereas we find them in Ba2IrO4 to be instead normally ordered.

View Article: PubMed Central - PubMed

Affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany.

ABSTRACT
A promising route to tailoring the electronic properties of quantum materials and devices rests on the idea of orbital engineering in multilayered oxide heterostructures. Here we show that the interplay of interlayer charge imbalance and ligand distortions provides a knob for tuning the sequence of electronic levels even in intrinsically stacked oxides. We resolve in this regard the d-level structure of layered Sr2IrO4 by electron spin resonance. While canonical ligand-field theory predicts g//-factors less than 2 for positive tetragonal distortions as present in Sr2IrO4, the experiment indicates g// is greater than 2. This implies that the iridium d levels are inverted with respect to their normal ordering. State-of-the-art electronic-structure calculations confirm the level switching in Sr2IrO4, whereas we find them in Ba2IrO4 to be instead normally ordered. Given the nonpolar character of the metal-oxygen layers, our findings highlight the tetravalent transition-metal 214 oxides as ideal platforms to explore d-orbital reconstruction in the context of oxide electronics.

No MeSH data available.


Related in: MedlinePlus

Planar IrO2 network in Sr2IrO4.(a) Coordination of the Ir site. Dashed lines show the boundaries of the crystallographic unit cell within a given IrO2 layer. (b) The point-group symmetry of the [Ir2O11] block is C2v; associated symmetry elements are indicated in the figure.
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f3: Planar IrO2 network in Sr2IrO4.(a) Coordination of the Ir site. Dashed lines show the boundaries of the crystallographic unit cell within a given IrO2 layer. (b) The point-group symmetry of the [Ir2O11] block is C2v; associated symmetry elements are indicated in the figure.

Mentions: To obtain ab initio quantum chemistry values for the inter-site effective magnetic couplings in Sr2IrO4 (see equation (1)), we carried out additional calculations on larger clusters that incorporate two 5d5 sites. The two-octahedra cluster has C2v symmetry (see Fig. 3), which implies a diagonal form for and in equation (1) (see Methods). By one-to-one correspondence between the MEs of the ab initio Hamiltonian


Orbital reconstruction in nonpolar tetravalent transition-metal oxide layers.

Bogdanov NA, Katukuri VM, Romhányi J, Yushankhai V, Kataev V, Büchner B, van den Brink J, Hozoi L - Nat Commun (2015)

Planar IrO2 network in Sr2IrO4.(a) Coordination of the Ir site. Dashed lines show the boundaries of the crystallographic unit cell within a given IrO2 layer. (b) The point-group symmetry of the [Ir2O11] block is C2v; associated symmetry elements are indicated in the figure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4491190&req=5

f3: Planar IrO2 network in Sr2IrO4.(a) Coordination of the Ir site. Dashed lines show the boundaries of the crystallographic unit cell within a given IrO2 layer. (b) The point-group symmetry of the [Ir2O11] block is C2v; associated symmetry elements are indicated in the figure.
Mentions: To obtain ab initio quantum chemistry values for the inter-site effective magnetic couplings in Sr2IrO4 (see equation (1)), we carried out additional calculations on larger clusters that incorporate two 5d5 sites. The two-octahedra cluster has C2v symmetry (see Fig. 3), which implies a diagonal form for and in equation (1) (see Methods). By one-to-one correspondence between the MEs of the ab initio Hamiltonian

Bottom Line: We resolve in this regard the d-level structure of layered Sr2IrO4 by electron spin resonance.This implies that the iridium d levels are inverted with respect to their normal ordering.State-of-the-art electronic-structure calculations confirm the level switching in Sr2IrO4, whereas we find them in Ba2IrO4 to be instead normally ordered.

View Article: PubMed Central - PubMed

Affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany.

ABSTRACT
A promising route to tailoring the electronic properties of quantum materials and devices rests on the idea of orbital engineering in multilayered oxide heterostructures. Here we show that the interplay of interlayer charge imbalance and ligand distortions provides a knob for tuning the sequence of electronic levels even in intrinsically stacked oxides. We resolve in this regard the d-level structure of layered Sr2IrO4 by electron spin resonance. While canonical ligand-field theory predicts g//-factors less than 2 for positive tetragonal distortions as present in Sr2IrO4, the experiment indicates g// is greater than 2. This implies that the iridium d levels are inverted with respect to their normal ordering. State-of-the-art electronic-structure calculations confirm the level switching in Sr2IrO4, whereas we find them in Ba2IrO4 to be instead normally ordered. Given the nonpolar character of the metal-oxygen layers, our findings highlight the tetravalent transition-metal 214 oxides as ideal platforms to explore d-orbital reconstruction in the context of oxide electronics.

No MeSH data available.


Related in: MedlinePlus