Nickelate Superconductivity without Rare-Earth Magnetism: (La,Sr)NiO2
Motoki Osada1,2, Bai Yang Wang1,3, Berit H Goodge4,5
1Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.
Advanced Materials (Deerfield Beach, Fla.)
|September 18, 2021
Summary
Researchers discovered superconductivity in lanthanum strontium nickelate (La,Sr)NiO2, finding it occurs even without rare-earth elements. This broadens the search for new superconductors in layered transition metal oxides.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Solid State Chemistry
Background:
- Unconventional superconductivity in cuprates drives research into other layered transition metal oxides.
- Superconductivity has recently been observed in infinite-layer nickelates like (Nd,Sr)NiO2 and (Pr,Sr)NiO2.
Purpose of the Study:
- To investigate superconductivity in La1-xSrxNiO2, specifically examining the role of rare-earth elements.
- To determine if superconductivity in infinite-layer nickelates is dependent on rare-earth magnetic moments.
Main Methods:
- Topotactic reduction of perovskite precursor phases to form infinite-layer nickelate thin films.
- Materials optimization and characterization of La1-xSrxNiO2 for x = 0.14 - 0.20.
- Measurement of low-temperature transport properties and superconducting transitions.
Main Results:
- Superconductivity was achieved in La1-xSrxNiO2 for x = 0.14 - 0.20, with a maximum onset temperature of approximately 9 K at x = 0.20.
- An unexpected superconducting ground state was observed in undoped LaNiO2, suggesting a self-doped electronic structure.
- A generalized superconducting dome was identified across (La/Pr/Nd)1-xSrxNiO2, correlating with unit cell volume and electron-hole population shifts.
Conclusions:
- Rare-earth moments are not essential for superconductivity in infinite-layer nickelates.
- La1-xSrxNiO2 represents a new platform for exploring unconventional superconductivity.
- The findings provide a broader understanding of superconductivity in this class of materials.
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