Charge and Spin Order Dichotomy in NdNiO_{2} Driven by the Capping Layer.
G Krieger1, L Martinelli2, S Zeng3
1Université de Strasbourg, CNRS, IPCMS UMR 7504, F-67034 Strasbourg, France.
Physical Review Letters
|July 22, 2022
Summary
Resonant inelastic x-ray scattering reveals that capping infinite-layer nickelate films with SrTiO3 enables magnon excitations, while uncapped films show a charge order signal that diminishes with doping. The capping layer
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- Infinite-layer nickelates exhibit superconductivity with similarities to cuprates.
- Both material classes share analogous structures and 3d-electron counts.
Purpose of the Study:
- Investigate electronic and magnetic excitations in Nd1-xSrxNiO2 thin films.
- Explore the impact of an SrTiO3 capping layer on these properties.
- Study charge density correlations and their relation to superconductivity.
Main Methods:
- Resonant inelastic x-ray scattering (RIXS).
- Fabrication of Nd1-xSrxNiO2 thin films with and without SrTiO3 capping.
- Analysis of magnon dispersion and elastic scattering peaks.
Main Results:
- Dispersing magnons were observed exclusively in capped nickelate films.
- Magnon signals progressively dampened with increasing doping levels.
- An elastic resonant scattering peak, indicative of charge order, was detected in uncapped x=0 samples at a specific wave vector.
- This charge order signal weakened at x=0.05 and vanished in the superconducting x=0.20 film.
Conclusions:
- The SrTiO3 capping layer plays a crucial role in enabling observable magnon excitations in infinite-layer nickelates.
- The presence and evolution of charge order are strongly linked to doping and the capping layer's influence.
- Further research is needed to understand the electronic reconstruction effects induced by the capping layer far from the interface.
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