Evidence of hydrogen content and monovalent Ni oxidation state in non-superconducting bulk anchored infinite-layer nickelates DOI Creative Commons
Javier Gainza, Carlos A. López, Federico Serrano‐Sánchez

и другие.

Cell Reports Physical Science, Год журнала: 2023, Номер 4(12), С. 101724 - 101724

Опубликована: Дек. 1, 2023

Since superconductivity was first reported in nickelate thin films, many studies have been published about this family of materials, and different hypotheses proposed for explaining the mechanisms structural dependence. Here, we report synthesis anchored infinite-layer LaNi0.9Al0.1O2.1 its hole-doped derivatives by topotactic reduction from La1−xSrxNi0.9Al0.1O3 rhombohedral perovskites. LaNiO2 constitute a new high-temperature superconductors, with same structure as high-Tc cuprates but based on nickel, only showing films now. We describe strategy to stabilize bulk: presence Al at octahedral sites helps stabilize/anchor structure. The reasons bulk being non-superconductors are hotly debated literature. An important question is whether there some hydrogen incorporated into during process LaNiO3 LaNiO2, predicted theoretically not experimentally. Our neutron powder diffraction data show that, indeed, occupies centers Ni–O squares, spectroscopic evidence EELS XAS suggests that Ni reduced Ni+ oxidation state, consistent crystallochemical data.

Язык: Английский

Three generations of infinite-layer nickelate crystals DOI Creative Commons
Y. Eren Suyolcu, Pascal Puphal, Matthias Hepting

и другие.

MRS Communications, Год журнала: 2025, Номер unknown

Опубликована: Фев. 3, 2025

Язык: Английский

Процитировано

0
Effects of different concentrations of topotactic hydrogen impurities on the electronic structure of nickelate superconductors DOI

Chenye Qin,

Mi Jiang, Liang Si

и другие.

Physical review. B./Physical review. B, Год журнала: 2023, Номер 108(15)

Опубликована: Окт. 26, 2023

Infinite-layer nickelate superconductors have recently been discovered to share both similarities and differences with cuprate superconductors. Notably, the incorporation of hydrogen (H) through topotactic reduction has found play a critical role in their electronic structure and, consequently, superconductivity. In this study, we utilized theoretical approach combining density-functional theory impurity approximation design three characteristic multi-orbital Hubbard models representing low, moderate, high concentrations topotactic-hydrogen. Consistent experimental findings, our simulations revealed that low topotactic-hydrogen induce high-spin states ($S=1)$ are composed by holes at ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ ${d}_{{z}^{2}}$ orbitals consequently emergent intersite hopping between is unfavorable for Conversely, an optimal concentration 25% H aligns single Ni-${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ band picture superconductivity infinite-layer nickelates, demonstrating its beneficial effect on promoting superconducting behavior.

Язык: Английский

Процитировано

7
Phase formation in hole- and electron-doped rare-earth nickelate single crystals DOI Creative Commons
Pascal Puphal, V. Sundaramurthy, V. Zimmermann

и другие.

APL Materials, Год журнала: 2023, Номер 11(8)

Опубликована: Авг. 1, 2023

The recent discovery of superconductivity in hole-doped infinite-layer nickelates has triggered a great interest the synthesis novel nickelate phases, which have primarily been examined thin film samples. Here, we report high-pressure optical floating zone (OFZ) growth various perovskite and perovskite-derived rare-earth single-crystals, investigate effects hole-, electron-, self-doping. For hole-doping with Ca Sr, observe phase separations during process when substitution level 8% is exceeded. A similar trend emerges for electron-doping Ce Zr. Employing lower doping levels allows us to grow sizeable crystals phase, exhibit significantly different electronic magnetic properties than undoped parent compounds, such as decreased resistivity suppressed response. Our insights into doping-dependent formation resulting synthesized reveal limitations opportunities exploration manipulation states nickelates.

Язык: Английский

Процитировано

6
On the Topotactic Phase Transition Achieving Superconducting Infinite‐Layer Nickelates DOI Creative Commons
Yan Li, Changjiang Liu, Hong Zheng

и другие.

Advanced Materials, Год журнала: 2024, Номер unknown

Опубликована: Сен. 1, 2024

Abstract Topotactic reduction is critical to a wealth of phase transitions current interest, including synthesis the superconducting nickelate Nd 0.8 Sr 0.2 NiO 2 , reduced from initial 3 /SrTiO heterostructure. Due highly sensitive and often damaging nature topotactic reduction, however, only handful research groups have been able reproduce superconductivity results. A series in situ synchrotron‐based investigations reveal that this due necessary formation an initial, ultrathin layer at surface helps mediate introduction hydrogen into film such apical oxygens are first removed / SrTiO (001) interface delivered reducing environment. This allows square‐planar perovskite stabilize propagate bottom top without interphase defects. Importantly, neither geometric rotations square planar structure nor significant incorporation within films detected, obviating its need for superconductivity. These findings unveil structural basis underlying transformation pathway provide important guidance on achieving systems.

Язык: Английский

Процитировано

2
Orbital-selective mixed-valent Mott/metal phase coexistence in NdNiO2 films DOI
L. Craco, Stefano Leoni

Physical Review Materials, Год журнала: 2023, Номер 7(4)

Опубликована: Апрель 18, 2023

A plethora of fundamentally different electronic states can coexist in orbital-selective systems, including Mott-localized, pseudogapped, Fermi, and non-Fermi-liquid phases. Understanding their emergence as a result correlations remains fundamental challenge condensed matter theory. Superconductivity infinite-layer nickelates is driven by subtle balance between valence charge crystal structures, two aspects that are strongly affected synthetic protocols. Here, using density functional plus dynamical mean-field theory, we explore correlation hole-doping-induced reconstruction the ${\mathrm{NdNiO}}_{2}$ superconductor. Based on direct comparison with extant RIXS data, show spectra films be understood mixed due to static modulation $3{d}^{9}/3{d}^{8}$ Mott/metal states. The coexistence Mott-localized $3{d}^{9}$ partially restored Fermi-liquid $3{d}^{8}$ low-energy excitations results two-fluid system exhibiting coupling parameters, novel scenario nickelate superconductors. We expect our present also applicable access phases other quantum which structural domains host doping levels.

Язык: Английский

Процитировано

4
Investigation of spin excitations and charge order in bulk crystals of the infinite-layer nickelate LaNiO2 DOI Creative Commons
Shohei Hayashida, V. Sundaramurthy, Pascal Puphal

и другие.

Physical review. B./Physical review. B, Год журнала: 2024, Номер 109(23)

Опубликована: Июнь 3, 2024

Recent x-ray spectroscopic studies have revealed spin excitations and charge density waves in thin films of infinite-layer (IL) nickelates. However, clarifying whether the origin these phenomena is intrinsic to material class or attributable impurity phases has presented a major challenge. Here we utilize topotactic methods synthesize bulk crystals IL nickelate LaNiO2 with crystallographically oriented surfaces. We examine using resonant inelastic scattering (RIXS) at Ni L3-edge elucidate correlations material. While detect presence prominent crystals, fingerprints order are absent ordering vectors identified previous thin-film studies. These results contribute understanding properties LaNiO2 establish topotactically synthesized as viable complementary specimens for investigations. Published by American Physical Society 2024

Язык: Английский

Процитировано

1
Amalgams as Hydrogen-Free Reducing Agents for Topotactic Oxide Deintercalation DOI
Thomas Whoriskey, Gregory Bassen, Brandon Wilfong

и другие.

Chemistry of Materials, Год журнала: 2024, Номер 36(9), С. 4583 - 4590

Опубликована: Апрель 30, 2024

Here, we report the development of a hydrogen-free, topotactic oxygen deintercalation technique using alkali metal aluminum gallium amalgams (AxAlGa, where A = Li, Na, K). These provide uniquely tunable system choice metal, its concentration, and Al:Ga composition alter reductive properties. We demonstrate utility this method in topotactically removing from bulk thin film specimens LnNiO3 (Ln La, Nd) to form infinite layer nickelate LnNiO2 Nd). For example, Na0.25AlGa affords LaNiO2 LaNiO3 at 300 °C for 120 h, while same amalgam 265 48 h intermediate La2Ni2O5 (LaNiO2.5). Other alterations time temperature as well (A) concentration (x) AxAlGa allow further exploration reduction. Compared standard techniques based on hydrogen gas or hydrides such LiH, NaH, CaH2, these offer an elegant tunability reduction potential, enabling control over rate degree removal without risk intercalation.

Язык: Английский

Процитировано

0
Unraveling nano-scale effects of topotactic reduction in LaNiO2 crystals DOI Creative Commons
Yu‐Mi Wu, Pascal Puphal, Masahiko Isobe

и другие.

APL Materials, Год журнала: 2024, Номер 12(9)

Опубликована: Сен. 1, 2024

Infinite-layer nickelates stand as a promising frontier in the exploration of unconventional superconductivity. Their synthesis through topotactic oxygen reduction from parent perovskite phase remains complex and elusive process. This study delves into nano-scale effects lattice transformation within LaNiO2 crystals. Leveraging high-resolution scanning transmission electron microscopy spectroscopy, our investigations uncover panorama structural alterations, including grain boundaries coherent twin boundaries, triggered by reduction-induced transformations. In addition, analyses unveil formation an oxygen-rich disordered transition encircling impurities pervading crystalline domains internal strain is accommodated boundary formation. By unraveling these effects, findings provide insights microscopic intricacies process elucidating to infinite-layer nickelate bulk

Язык: Английский

Процитировано

0
Evidence of hydrogen content and monovalent Ni oxidation state in non-superconducting bulk anchored infinite-layer nickelates DOI Creative Commons
Javier Gainza, Carlos A. López, Federico Serrano‐Sánchez

и другие.

Cell Reports Physical Science, Год журнала: 2023, Номер 4(12), С. 101724 - 101724

Опубликована: Дек. 1, 2023

Since superconductivity was first reported in nickelate thin films, many studies have been published about this family of materials, and different hypotheses proposed for explaining the mechanisms structural dependence. Here, we report synthesis anchored infinite-layer LaNi0.9Al0.1O2.1 its hole-doped derivatives by topotactic reduction from La1−xSrxNi0.9Al0.1O3 rhombohedral perovskites. LaNiO2 constitute a new high-temperature superconductors, with same structure as high-Tc cuprates but based on nickel, only showing films now. We describe strategy to stabilize bulk: presence Al at octahedral sites helps stabilize/anchor structure. The reasons bulk being non-superconductors are hotly debated literature. An important question is whether there some hydrogen incorporated into during process LaNiO3 LaNiO2, predicted theoretically not experimentally. Our neutron powder diffraction data show that, indeed, occupies centers Ni–O squares, spectroscopic evidence EELS XAS suggests that Ni reduced Ni+ oxidation state, consistent crystallochemical data.

Язык: Английский

Процитировано

0