Quantifying the critical thickness of electron hybridization in spintronics materials.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28714466.
- Also identified by DOI 10.1038/ncomms16051 and PMC identifier 5520016.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
In the rapidly growing field of spintronics, simultaneous control of electronic and magnetic properties is essential, and the perspective of building novel phases is directly linked to the control of tuning parameters, for example, thickness and doping. Looking at the relevant effects in interface-driven spintronics, the reduced symmetry at a surface and interface corresponds to a severe modification of the overlap of electron orbitals, that is, to a change of electron hybridization. Here we report a chemically and magnetically sensitive depth-dependent analysis of two paradigmatic systems, namely La<sub>1-x</sub>Sr<sub>x</sub>MnO<sub>3</sub> and (Ga,Mn)As. Supported by cluster calculations, we find a crossover between surface and bulk in the electron hybridization/correlation and we identify a spectroscopic fingerprint of bulk metallic character and ferromagnetism versus depth. The critical thickness and the gradient of hybridization are measured, setting an intrinsic limit of 3 and 10 unit cells from the surface, respectively, for (Ga,Mn)As and La<sub>1-x</sub>Sr<sub>x</sub>MnO<sub>3</sub>, for fully restoring bulk properties.