Transition metal oxide interfaces have garnered great attention due to their fascinating properties that are absent in their bulk counterparts. The high mobility and coexistence of superconductivity and magnetism at these interfaces remain compelling research topics. Here, we first report superconductivity in the 2DEG formed at the LaFeO/SrTiO interfaces, characterized by a superconducting transition temperature () of 333 mK and a superconducting layer thickness of 13.
View Article and Find Full Text PDFVan der Waals integration of freestanding perovskite-oxide membranes with two-dimensional semiconductors has emerged as a promising strategy for developing high-performance electronics, such as field-effect transistors. In these innovative field-effect transistors, the oxide membranes have primarily functioned as dielectric layers, yet their great potential for structural tunability remains largely untapped. Free of epitaxial constraints by the substrate, these freestanding membranes exhibit remarkable structural tunability, providing a unique material system to achieve huge strain gradients and pronounced flexoelectric effects.
View Article and Find Full Text PDFThe observation of superconductivity in infinite-layer nickelates has attracted significant attention due to its potential as a new platform for exploring high-T superconductivity. However, thus far, superconductivity has only been observed in epitaxial thin films, which limits the manipulation capabilities and modulation methods compared to two-dimensional exfoliated materials. Given the exceptionally giant strain tunability and stacking capability of freestanding membranes, separating superconducting nickelates from the as-grown substrate is a novel way to engineer the superconductivity and uncover the underlying physics.
View Article and Find Full Text PDFSince 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 proven to be challenging. Here, an ultrahigh vacuum (UHV) reduction method is developed using atomic hydrogen as a reducing agent and is applied in the lanthanum nickelate system.
View Article and Find Full Text PDFAfter being expected to be a promising analog to cuprates for decades, superconductivity has recently been discovered in infinite-layer nickelates, providing new opportunities to explore mechanisms of high-temperature superconductivity. However, in sharp contrast to the single-band and anisotropic superconductivity in cuprates, nickelates exhibit a multi-band electronic structure and an unexpected isotropic superconductivity as reported recently, which challenges the cuprate-like picture in nickelates. Here, it is shown that strong anisotropic magnetotransport behaviors exist in La-based nickelate films with enhanced crystallinity and superconductivity ( = 18.
View Article and Find Full Text PDFThe increasing miniaturization of electronics requires a better understanding of material properties at the nanoscale. Many studies have shown that there is a ferroelectric size limit in oxides, below which the ferroelectricity will be strongly suppressed due to the depolarization field, and whether such a limit still exists in the absence of the depolarization field remains unclear. Here, by applying uniaxial strain, we obtain pure in-plane polarized ferroelectricity in ultrathin SrTiO_{3} membranes, providing a clean system with high tunability to explore ferroelectric size effects especially the thickness-dependent ferroelectric instability with no depolarization field.
View Article and Find Full Text PDFTuning the ferroelectric domain structure by a combination of elastic and electrostatic engineering provides an effective route for enhanced piezoelectricity. However, for epitaxial thin films, the clamping effect imposed by the substrate does not allow aftergrowth tuning and also limits the electromechanical response. In contrast, freestanding membranes, which are free of substrate constraints, enable the tuning of a subtle balance between elastic and electrostatic energies, giving new platforms for enhanced and tunable functionalities.
View Article and Find Full Text PDFThe corrosion of the support in proton-exchange membrane fuel cells (PEMFCs) is a major obstacle to their development. In this study, we combined the excellent corrosion resistance and strong metal-support interaction (SMSI) provided by titanium nitride (TiN) with the excellent conductivity of carbon to construct a TiN@C composite support composed of a TiN core and a porous carbon nanolayer shell. The composite TiN@C support exhibited a higher corrosion resistance than the carbon support during testing at 1.
View Article and Find Full Text PDFFerroelectric domain wall memories have been proposed as a promising candidate for nonvolatile memories, given their intriguing advantages including low energy consumption and high-density integration. Perovskite oxides possess superior ferroelectric prosperities but perovskite-based domain wall memory integrated on silicon has rarely been reported due to the technical challenges in the sample preparation. Here, we demonstrate a domain wall memory prototype utilizing freestanding BaTiO membranes transferred onto silicon.
View Article and Find Full Text PDFTopological domains in ferroelectrics have received much attention recently owing to their novel functionalities and potential applications in electronic devices. So far, however, such topological polar structures have been observed only in superlattices grown on oxide substrates, which limits their applications in silicon-based electronics. Here we report the realization of room-temperature skyrmion-like polar nanodomains in lead titanate/strontium titanate bilayers transferred onto silicon.
View Article and Find Full Text PDFInterfacial thermal transport plays a prominent role in the thermal management of nanoscale objects and is of fundamental importance for basic research and nanodevices. At metal/insulator interfaces, a configuration commonly found in electronic devices, heat transport strongly depends upon the effective energy transfer from thermalized electrons in the metal to the phonons in the insulator. However, the mechanism of interfacial electron-phonon coupling and thermal transport at metal/insulator interfaces is not well understood.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2021
Perovskite oxide SrTiO can be electron-doped and exhibits high mobility by introducing oxygen vacancies or dopants such as Nb or La. A reversible after-growth tuning of high mobility carriers in SrTiO is highly desired for the applications in high-speed electronic devices. Here, we report the observation of tunable high-mobility electrons in layered perovskite/perovskite (SrTiO/SrTiO) heterostructure.
View Article and Find Full Text PDFTwo-dimensional (2D) materials such as graphene and transition-metal dichalcogenides reveal the electronic phases that emerge when a bulk crystal is reduced to a monolayer. Transition-metal oxide perovskites host a variety of correlated electronic phases, so similar behaviour in monolayer materials based on transition-metal oxide perovskites would open the door to a rich spectrum of exotic 2D correlated phases that have not yet been explored. Here we report the fabrication of freestanding perovskite films with high crystalline quality almost down to a single unit cell.
View Article and Find Full Text PDFJ Phys Condens Matter
June 2019
SrCrWO/SrFeMoO (SCWO/SFMO) superlattices with 4, 6, 7, 10 periods (abbreviated as S-1, S-2, S-3, and S-4) were prepared on (0 0 1) SrTiO (STO) substrates by pulsed laser deposition. All superlattices show macroscopic ferromagnetic behavior, and the magnetization increases with increasing period. The S-1 superlattice demonstrates semiconductor-like temperature-dependent resistivity in the whole measuring temperature range and negative magnetoresistance of -5.
View Article and Find Full Text PDFA novel cathode structure consisting of ultrathin and freestanding surface-nitrided porous titanium (SNPT) sheets, was designed for high-gravimetric-capacity Li-S batteries. This unusual cathode combines the sulfur host and the current collector together, increasing the sulfur mass ratio by over 20% compared with routine cathodes, resulting in excellent cycling performance with an initial capacity of 1325 mA h g-1 and a coulombic efficiency of over 99% at 1.0C.
View Article and Find Full Text PDFIn van der Waals epitaxial growth, the substrate plays a particularly important role in the crystal morphology. Here, we synthesized MoS by chemical vapour deposition on silicon carbide (SiC). The obtained MoS dendritic crystals show six-fold symmetry, which are different from the conventional triangular shapes on SiO substrate and from those with three-fold symmetry on SrTiO substrate.
View Article and Find Full Text PDFMagnetoresistance (MR) is the magnetic field-induced change of electrical resistance. The MR effect not only has wide applications in hard drivers and sensors but also is a long-standing scientific issue for complex interactions. Ferromagnetic/ferrimagnetic oxides generally show negative MR due to the magnetic field-induced spin order.
View Article and Find Full Text PDFTwo obstacles hindering solar energy conversion by photoelectrochemical (PEC) water-splitting devices are the charge separation and the transport efficiency at the photoanode-electrolyte interface region. Herein, core-shell-structured Ni@Ni(OH) nanoparticles were electrodeposited on the surface of an n-type Si photoanode. The Schottky barrier between Ni and Si is sensitive to the thickness of the Ni(OH) shell.
View Article and Find Full Text PDFJ Phys Condens Matter
March 2013
The thickness-dependent metal-insulator transition is observed in meta-stable orthorhombic SrIrO3 thin films synthesized by pulsed laser deposition. SrIrO3 films with thicknesses less than 3 nm demonstrate insulating behaviour, whereas those thicker than 4 nm exhibit metallic conductivity at high temperature, and insulating-like behaviour at low temperature. Weak/Anderson localization is mainly responsible for the observed thickness-dependent metal-insulator transition in SrIrO3 films.
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