$\text{In situ}$ preparation of superconducting infinite-layer nickelate thin films with atomically flat surface

Abstract

Since their discovery, the infinite-layer nickelates have been regarded as an appealing system for gaining deeper insights into high temperature superconductivity (HTSC). However, the synthesis of superconducting samples has been proved to be challenging. Here, we develop an ultrahigh vacuum (UHV) $\text{in situ}$ reduction method using atomic hydrogen as reducing agent and apply it in lanthanum nickelate system. The reduction parameters, including the reduction temperature (${\text{T}}_{\mathrm{R}}$) and hydrogen pressure (${\text{P}}_{\mathrm{H}}$), are systematically explored. We found that the reduction window for achieving superconducting transition is quite wide, reaching nearly 80${}^{\circ }$C in ${\text{T}}_{\mathrm{R}}$ and 3 orders of magnitude in ${\text{P}}_{\mathrm{H}}$ when the reduction time is set to 30 mins. And there exists an optimal ${\text{P}}_{\mathrm{H}}$ for achieving the highest ${\text{T}}_{\mathrm{c}}$ if both ${\text{T}}_{\mathrm{R}}$ and reduction time are fixed. More prominently, as confirmed by atomic force microscopy and scanning transmission electron microscopy, the atomically flat surface can be preserved during the $\text{in situ}$ reduction process, providing advantages over the $\text{ex situ}$ CaH${}_2$ method for surface-sensitive experiments.

5 pages, 4 figures

References in corpus (9)

• Nickelate superconductivity without rare-earth magnetism: (La,Sr)NiO${}_2$
• Superconductivity in infinite-layer nickelate La${}_{1-x}$Ca${}_x$NiO${}_2$ thin films
• Phase Diagram of Infinite Layer Praseodymium Nickelate Pr${}_{1-x}$Sr${}_x$NiO${}_2$ Thin Films
• Reconstructing the polar interface of infinite-layer nickelate thin films
• Absence of $3a_0$ Charge Density Wave Order in the Infinite Layer Nickelates
• Impact of Cation Stoichiometry on the Crystalline Structure and Superconductivity in Nickelates
• Synthesis of infinite-layer nickelates and influence of the capping-layer on magnetotransport
• Synthesis of thin film infinite-layer nickelates by atomic hydrogen reduction: clarifying the role of the capping layer
• Emergent electronic landscapes in a novel valence-ordered nickelate with tri-component nickel coordination

Cited by in corpus (6)

• Electronic Structure of Superconducting Infinite-Layer Lanthanum Nickelates
• Superconductivity in PrNiO2 infinite-layer nickelates
• Synthesis of thin film infinite-layer nickelates by atomic hydrogen reduction: clarifying the role of the capping layer
• Gigantic-oxidative atomic-layer-by-layer epitaxy for artificially designed complex oxides
• Chemical control of polymorphism and ferroelectricity in PbTiO3 and SrTiO3 monolayers and bilayers
• Achieving superconductivity in infinite-layer nickelate thin films by aluminum sputtering deposition