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Atomic scale disorder and reconstruction in bulk infinite-layer nickelates lacking superconductivity
Kejun Hu1, Qing Li2, Dongsheng Song3
1Information Materials and Intelligent Sensing Laboratory of Anhui Province, Anhui Key Laboratory of Magnetic Functional Materials and Devices, Institutes of Physical Science and Information Technology, Anhui University, Hefei, China.
Nature Communications
|June 14, 2024
Summary
Structural defects and interstitial oxygen atoms in bulk infinite-layer nickelates hinder superconductivity. These atomic imperfections disrupt crystal structures, leading to insulating properties and preventing the emergence of superconductivity in these materials.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Solid-State Chemistry
Background:
- Superconductivity in infinite-layer nickelate films has recently been discovered, expanding the range of known superconductors.
- The infinite-layer structure and chemical doping are critical for superconductivity, but its absence in bulk nickelates is not well understood.
Purpose of the Study:
- Investigate the atomic defects and electronic structures in bulk infinite-layer Nd0.8Sr0.2NiO2.
- Identify the reasons for the lack of superconductivity in bulk infinite-layer nickelates.
Main Methods:
- Scanning transmission electron microscopy (STEM) was employed to examine bulk infinite-layer Nd0.8Sr0.2NiO2.
- Analysis of atomic defects and electronic structures within the material.
Main Results:
- Three-dimensional block-like structural domains, formed by intersecting defects, were observed, disrupting crystal continuity.
- Interstitial oxygen atoms were found on the Nd atomic plane in bulk nickelates due to incomplete topotactic reduction.
- These defects and oxygen interstitials likely cause local distortions and contribute to the insulating character, inhibiting superconductivity.
Conclusions:
- Structural and atomic defects play a crucial role in the insulating nature of bulk nickelates.
- Incomplete topotactic reduction and resulting interstitial oxygen atoms further impede superconductivity.
- Understanding these defects is key to developing bulk infinite-layer nickelate superconductors.
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