Signature of Superconductivity in Pressurized La₄Ni₃O₁₀

Chinese Physics Letters, Год журнала: 2023, Номер 41(1), С. 017401 - 017401

Опубликована: Дек. 14, 2023

The discovery of high-temperature superconductivity near 80 K in bilayer nickelate La 3 Ni 2 O 7 under high pressures has renewed the exploration superconducting bulk materials. extension other nickelates a broader family is also essential. Here, we report experimental observation signature trilayer 4 10 pressures. By using modified sol-gel method and post-annealing treatment oxygen pressure, successfully obtained polycrystalline samples with different transport behaviors at ambient pressure. Then performed high-pressure electrical resistance measurements on these diamond-anvil-cell apparatus. Surprisingly, possible transition maximum temperature ( T c ) about 20 observed, as evidenced by clear drop suppression drops magnetic fields. Although sample-dependent relatively small, it appears all our measured samples. We argue that observed signal most likely to originate from main phase . Our findings will motivate shed light understanding underlying mechanisms high- nickelates.

Язык: Английский

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Strain-mediated phase crossover in Ruddlesden–Popper nickelates

Communications Materials, Год журнала: 2024, Номер 5(1)

Опубликована: Март 13, 2024

Abstract Recent progress on the signatures of pressure-induced high-temperature superconductivity in Ruddlesden–Popper (RP) nickelates (La n +1 Ni O 3 ) has attracted growing interest both theoretical calculations and experimental efforts. The fabrication high-quality single-crystalline RP nickelate thin films is critical for possible reducing superconducting transition pressure advancing applications microelectronics future. In this study, we report observations an active phase induced by misfit strain. We found that favor perovskite structure ( = ∞) under tensile strains, while compressive strains stabilize La 2 7 2) phase. selection distinct phases governed strain dependent formation energy electronic configuration. compressively strained , experimentally determined e g splitting ~0.2 eV electrons prefer to occupy in-plane orbitals. First-principles unveil a robust coupling between effects valence state ions nickelates, suggesting dual driving force inevitable co-existence nickelates. Our work underscores sensitivity epitaxial strain, presenting significant challenge fabricating pure-phase films. Therefore, special attention stacking defects grain boundaries different essential when discussing

Язык: Английский

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Advances in complex oxide quantum materials through new approaches to molecular beam epitaxy

Journal of Physics D Applied Physics, Год журнала: 2024, Номер 57(19), С. 193001 - 193001

Опубликована: Фев. 2, 2024

Abstract Molecular beam epitaxy (MBE), a workhorse of the semiconductor industry, has progressed rapidly in last few decades development novel materials. Recent developments condensed matter and materials physics have seen rise many quantum that require ultra-clean high-quality samples for fundamental studies applications. Novel oxide-based synthesized using MBE advanced field In this review, we discuss recent progress new techniques enabled synthesis complex oxides exhibit ‘quantum’ phenomena, including superconductivity topological electronic states. We show how these produced breakthroughs 4d 5d oxide films heterostructures are particular interest as These offer bright future ultra-high quality

Язык: Английский

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Cuprate-like electronic structures in infinite-layer nickelates with substantial hole dopings

National Science Review, Год журнала: 2024, Номер 11(8)

Опубликована: Июнь 4, 2024

ABSTRACT Superconducting infinite-layer (IL) nickelates offer a new platform for investigating the long-standing problem of high-temperature superconductivity. Many models were proposed to understand superconducting mechanism based on calculated electronic structure, and multiple Fermi surfaces orbitals involved create complications controversial conclusions. Over past five years, lack direct measurements structure has hindered understanding nickelate superconductors. Here we fill this gap by directly resolving structures parent compound LaNiO2 La0.8Ca0.2NiO2 using angle-resolved photoemission spectroscopy. We find that their consist quasi-2D hole pocket 3D electron at Brillouin zone corner, whose volumes change upon Ca doping. The surface topology band dispersion closely resemble those observed in hole-doped cuprates. However, cuprate-like exhibits significantly higher doping compared cuprates, highlighting disparities states phase. Our observations highlight novel aspects IL nickelates, pave way toward microscopic family its

Язык: Английский

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Synthesis of thin film infinite-layer nickelates by atomic hydrogen reduction: Clarifying the role of the capping layer

APL Materials, Год журнала: 2024, Номер 12(3)

Опубликована: Март 1, 2024

We present an integrated procedure for the synthesis of infinite-layer nickelates using molecular-beam epitaxy with gas-phase reduction by atomic hydrogen. first discuss challenges in growth and characterization perovskite NdNiO3/SrTiO3, arising from post crack formation stoichiometric films. then detail a fully reducing NdNiO3 films to phase, NdNiO2, hydrogen; resulting display excellent structural quality, smooth surfaces, lower residual resistivities than reduced other methods. utilize situ nature this technique investigate role that SrTiO3 capping layers play process, illustrating their importance preventing secondary phases at exposed nickelate surface. A comparative bulk- surface-sensitive study indicates polycrystalline crust on film surface serves limit process.

Язык: Английский

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Superconductivity in PrNiO₂ Infinite‐Layer Nickelates

Advanced Materials, Год журнала: 2025, Номер unknown

Опубликована: Март 10, 2025

Several reports about infinite-layer nickelate thin films suggest that the superconducting critical temperature versus chemical doping phase diagram has a dome-like shape, similar to cuprates. Here, highly reproducible state in undoped PrNiO2 grown on SrTiO3 are demonstrated. Scanning transmission electron microscopy measurements show coherent with no visible stacking-fault defects, an overall high structural quality where possible unintentional or interstitial oxygen, if present, sum well below measurable threshold of technique. X-ray absorption very sharp features at Ni L3,2-edges large linear dichroism, indicating preferential hole occupation Ni1+-3 dx2-y2${\rm d}_{x^2-y^2}$ orbitals square planar geometry. Resonant inelastic scattering reveal magnon excitations 200 meV energy magnetic Brillouin zone boundary, resonant Ni1 + peak. The results indicate that, when properly stabilized, without doping.

Язык: Английский

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Superconductivity in an ultrathin multilayer nickelate

Science Advances, Год журнала: 2025, Номер 11(1)

Опубликована: Янв. 1, 2025

We report the appearance of superconductivity in single-unit-cell Nd 6 Ni 5 O 12 , exhibiting a transition temperature similar to that thicker films. In situ synchrotron x-ray scattering performed during growth parent phase, 16 shows necessary layer-by-layer deposition sequence does not follow formula unit but an alternate order due relative stability perovskite cell. exploit this insight grow ultrathin heterostructures and conduct studies topotactic reduction, finding formation square-planar phase occurs rapidly is highly sensitive reduction temperature, with small deviations from optimum condition leading inhomogeneity loss superconductivity. The fluorite layer within cell facilitates by initially stabilizing upper half Our findings provide into Ruddlesden-Popper nickelates, highlighting need for metastable phases key

Язык: Английский

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Superconductivity in the Parent Infinite-Layer Nickelate NdNiO2

Physical Review X, Год журнала: 2025, Номер 15(2)

Опубликована: Май 12, 2025

We report evidence for superconductivity with onset temperatures up to 11 K in thin films of the infinite-layer nickelate parent compound NdNiO2. A combination oxide molecular beam epitaxy and atomic hydrogen reduction yields samples high crystallinity low residual resistivities, a substantial fraction which exhibit superconducting transitions. survey large series variety techniques, including electrical transport, scanning transmission electron microscopy, x-ray absorption spectroscopy, resonant inelastic scattering, investigate possible origins superconductivity. propose that could be intrinsic undoped nickelates but suppressed by disorder due possibly sign-changing order parameter, finding would necessitate reconsideration phase diagram. Another hypothesis is materials can hole doped from randomly dispersed apical oxygen atoms, suggest an alternative pathway achieving Published American Physical Society 2025

Язык: Английский

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Toward Reliable Synthesis of Superconducting Infinite Layer Nickelate Thin Films by Topochemical Reduction

Advanced Science, Год журнала: 2024, Номер 11(24)

Опубликована: Апрель 18, 2024

Abstract Infinite layer (IL) nickelates provide a new route beyond copper oxides to address outstanding questions in the field of unconventional superconductivity. However, their synthesis poses considerable challenges, largely hindering experimental research on this class oxide superconductors. That is achieved two‐step process that yields most thermodynamically stable perovskite phase first, then IL by topotactic reduction, quality starting playing crucial role. Here, reliable superconducting nickelate films reported after successive topochemical reductions parent with nearly optimal stoichiometry. Careful analysis transport properties incompletely reduced reveals an improvement strange metal behavior normal state resistivity over subsequent reductions, offering insight into reduction process.

Язык: Английский

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Origin of a Topotactic Reduction Effect for Superconductivity in Infinite-Layer Nickelates

Physical Review Letters, Год журнала: 2024, Номер 133(6)

Опубликована: Авг. 8, 2024

Topotactic reduction utilizing metal hydrides as reagents has emerged an effective approach to achieve exceptionally low oxidization states of ions and unconventional coordination networks. This method opens avenues the development entirely new functional materials, with one notable example being infinite-layer nickelate superconductors. However, effect on atomic reconstruction electronic structures-crucial for superconductivity-remains largely unresolved. We designed two sets control Nd_{0.8}Sr_{0.2}NiO_{2} thin films used secondary ion mass spectroscopy highlight absence reduction-induced hydrogen intercalation. X-ray absorption revealed a significant linear dichroism dominant Ni 3d_{x2-y2} orbitals superconducting samples, indicating single-band nature nickelates. Consistent T_{c}, 3d asymmetry manifests domelike dependence duration. Our results unveil critical role in modulating Ni-3d orbital polarization its impact properties.

Язык: Английский

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