Evidence for Anisotropic Superconductivity Beyond Pauli Limit in Infinite‐Layer Lanthanum Nickelates

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(32)

Published: May 26, 2023

After being expected as a promising analogue to cuprates for decades, superconductivity was recently discovered in infinite-layer nickelates, providing new opportunities explore mechanisms of high-temperature superconductivity. However, sharp contrast the single-band quasi-two-dimensional cuprates, nickelates exhibit multi-band electronic structure and an unexpected isotropic reported recently, which challenges cuprate-like picture nickelates. Here, we show is actually anisotropic nature, that cuprates. By synthesizing high-quality lanthanide nickelate films with enhanced crystallinity ($T_{c}^{onset}$ = 18.8 K, $T_{c}^{zero}$ 16.5 K), strong magnetotransport behaviors have been observed. The nature further confirmed by existence cusp-like peak angle-dependent $T_{c}$, Berezinskii-Kosterlitz-Thouless transition near $T_{c}$. Our work thus suggests implying single-3$d_{x^2-y^2}$-band may remain valid these compounds.

Language: Английский

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Progress and prospects in two-dimensional magnetism of van der Waals materials

Progress in Quantum Electronics, Journal Year: 2024, Volume and Issue: 93, P. 100498 - 100498

Published: Jan. 1, 2024

Language: Английский

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Superconductivity in Freestanding Infinite‐Layer Nickelate Membranes

Advanced Materials, Journal Year: 2024, Volume and Issue: 36(31)

Published: June 7, 2024

Abstract The observation of superconductivity in infinite‐layer nickelates has attracted significant attention due to its potential as a new platform for exploring high‐ T c superconductivity. However, thus far, only been observed epitaxial thin films, which limits the manipulation capabilities and modulation methods compared two‐dimensional exfoliated materials. Given exceptionally giant strain tunability stacking capability freestanding membranes, separating superconducting from as‐grown substrate is novel way engineer uncover underlying physics. Herein, this work reports synthesis La 0.8 Sr 0.2 NiO 2 membranes (), emphasizing crucial roles interface engineering precursor phase film growth quick transfer process achieving This offers versatile investigating nickelates, such pairing symmetry via constructing Josephson tunneling junctions higher values high‐pressure experiments.

Language: Английский

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Electronic structure and magnetic correlations in the trilayer nickelate superconductor La4Ni3O10 under pressure

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 109(23)

Published: June 11, 2024

It has been recently shown that under pressure trilayer Ruddlesden-Popper nickelate ${\mathrm{La}}_{4}{\mathrm{Ni}}_{3}{\mathrm{O}}_{10}$ (LNO) becomes superconducting below a critical temperature $\ensuremath{\approx}20$ K, in addition to the infinite-layer and bilayer systems. Motivated by this observation, we explore effects of electron correlations on its electronic structure magnetic properties using advanced density functional theory plus dynamical mean-field approach. Our results for normal-state correlation LNO show much common with nickelates, remarkable site- orbital-dependent renormalizations Ni $3d$ bands notable incoherence ${d}_{3{z}^{2}\ensuremath{-}{r}^{2}}$ states, caused effects. analysis Fermi surface suggests emergence competing spin charge stripe implying importance in-plane fluctuations explain superconductivity material.

Language: Английский

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Nature of charge density waves and metal-insulator transition in pressurized La3Ni2O7

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 110(14)

Published: Oct. 18, 2024

${\mathrm{La}}_{3}{\mathrm{Ni}}_{2}{\mathrm{O}}_{7}$ has garnered widespread interest recently due to its high-temperature superconductivity under pressure, accompanied by charge density wave (CDW) ordering and metal-insulator (MI) transitions in the phase diagram. Here, we explore nature of CDW MI using comprehensive first-principles calculations. Our findings reveal that possesses an antiferromagnetic ground state both low high pressures, with strong Fermi surface nesting contributed flat band leads phonon softening electronic instabilities. Accordingly, several stable orders oxygen octahedral distortions are identified. In presence apical vacancies, identify two different phases exhibiting similar phases, their competition can lead a pressure-induced transition. The estimated transition temperature pressure agree nicely experiments. addition, find electron-phonon coupling is too weak contribute superconductivity. These results suggest unconventional superconducting pairing mechanism mediated fluctuations. Finally, present diagram consistent experimental results. offer crucial insights into interplay superconductivity, CDW, role vacancies pressurized ${\mathrm{La}}_{3}{\mathrm{Ni}}_{2}{\mathrm{O}}_{7}$.

Language: Английский

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

Physical Review Letters, Journal Year: 2024, Volume and Issue: 133(6)

Published: Aug. 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.

Language: Английский

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Superconductivity in an ultrathin multilayer nickelate

Science Advances, Journal Year: 2025, Volume and Issue: 11(1)

Published: Jan. 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

Language: Английский

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Synthesis and physical properties of LaNiO2 crystals

Physical Review Materials, Journal Year: 2023, Volume and Issue: 7(1)

Published: Jan. 30, 2023

Infinite-layer (IL) nickelates are an emerging family of superconductors whose similarities and differences to cuprate under intense debate. To date, the IL phase can only be reached via topotactic oxygen reduction perovskite phase, using H$_2$ gas or reducing agents such as CaH$_2$. While method has been widely employed on thin film polycrystalline powder samples, La$_{1-x}$Ca$_x$NiO$_3$ single-crystals with lateral dimensions up 150 $\mu$m was achieved recently, indirect contact Here we report transformation much larger LaNiO$_3$ crystals more than one millimeter, direct We characterize crystalline, magnetic, electronic properties obtained LaNiO$_{2}$ by single-crystal x-ray diffraction (XRD), magnetometry, electrical transport, photoelectron spectroscopy (XPS) measurements. The amount incorporated hydrogen due process is determined a extraction method. In addition, investigate evolution lattice parameters hydrostatic pressure 12 GPa, high-resolution synchrotron XRD. Furthermore, provide comparison several physical their counterparts.

Language: Английский

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Electronic structure, dimer physics, orbital-selective behavior, and magnetic tendencies in the bilayer nickelate superconductor La$_3$Ni$_2$O$_7$ under pressure

arXiv (Cornell University), Journal Year: 2023, Volume and Issue: unknown

Published: Jan. 1, 2023

Motivated by the recently reported high-temperature superconductivity in bilayer La$_3$Ni$_2$O$_7$ (LNO) under pressure, here we comprehensively study this system using {\it ab initio} techniques. The Ni $3d$ orbitals have a large bandwidth at ambient increasing $\sim 22\%$ 29.5 Gpa. Without electronic interactions, $d_{3z^2-r^2}$ form bonding-antibonding molecular orbital state via O $p_z$ inducing ``dimer'' lattice LNO bilayers. Fermi surface consists of two-electron sheets with mixed $e_g$ and hole pocket defined orbital, suggesting two-orbital minimum model. Different from infinite-layer nickelate, obtained interorbital} hopping between $d_{x^2-y^2}$ states LNO, caused ligand ``bridge'' in-plane $p_x$ or $p_y$ connecting those two orbitals, $d-p$ $\sigma$-bonding characteristics. competition intraorbital interorbital hoppings leads to an interesting dominant spin stripe ($\pi$, 0) order because bond ferromagnetic tendencies discussed ``half-empty'' mechanism.

Language: Английский

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Atomic scale disorder and reconstruction in bulk infinite-layer nickelates lacking superconductivity

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: June 14, 2024

Abstract The recent discovery of superconductivity in infinite-layer nickelate films has sparked significant interest and expanded the realm superconductors, which structure proper chemical doping are both essence. Nonetheless, reasons for absence bulk nickelates remain puzzling. Herein, we investigate atomic defects electronic structures Nd 0.8 Sr 0.2 NiO 2 using scanning transmission electron microscopy. Our observations reveal presence three-dimensional (3D) block-like structural domains resulting from intersecting defect structures, disrupting continuity within crystal grains, could be a crucial factor giving rise to insulating character inhibiting emergence superconductivity. Moreover, structure, without complete topotactic reduction, retains interstitial oxygen atoms on plane nickelates, possibly further aggravating local distortions planes hindering These findings shed light existence provide valuable insights into influence reduction orders

Language: Английский

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