Suppressing Structure Delamination for Enhanced Electrochemical Performance of Solid Oxide Cells.

Reversible solid oxide cells (rSOCs) have significant potential as efficient energy conversion and storage systems. Nevertheless, the practical application of their conventional air electrodes, such as LaSrMnO (LSM), BaSrCoFeO (BSCF), and PrBaCaCoO (PBCC), remains unsatisfactory due to interface delamination during prolonged electrochemical operation. Using micro-focusing X-ray absorption spectroscopy (µ-XAS), a decrease (increase) in the co-valence state from the electrode surface to the electrode/electrolyte interface is observed, leading to the above delamination.

Correlated order at the tipping point in the kagome metal CsVSb.

Spontaneously broken symmetries are at the heart of many phenomena of quantum matter and physics more generally. However, determining the exact symmetries that are broken can be challenging due to imperfections such as strain, in particular when multiple electronic orders are competing. This is exemplified by charge order in some kagome systems, where evidence of nematicity and flux order from orbital currents remains inconclusive due to contradictory measurements.

Using strain to uncover the interplay between two- and three-dimensional charge density waves in high-temperature superconducting YBaCuO.

Uniaxial pressure provides an efficient approach to control charge density waves in YBaCuO. It can enhance the correlation volume of ubiquitous short-range two-dimensional charge-density-wave correlations, and induces a long-range three-dimensional charge density wave, otherwise only accessible at large magnetic fields. Here, we use x-ray diffraction to study the strain dependence of these charge density waves and uncover direct evidence for a form of competition between them.

Modulating 3d Charge State via Halogen Ions in Neighboring Molecules of Metal-Organic Frameworks for Improving Water Oxidation.

Modulating the coordination environment of the metal active center is an effective method to boost the catalytic performances of metal-organic frameworks (MOFs) for oxygen evolution reaction (OER). However, little attention has been paid to the halogen effects on the ligands engineering. Herein, a series of MOFs X─FeNi-MOFs (X = Br, Cl, and F) is constructed with different coordination microenvironments to optimize OER activity.

Three-dimensional spin-wave dynamics, localization and interference in a synthetic antiferromagnet.

Spin waves are collective perturbations in the orientation of the magnetic moments in magnetically ordered materials. Their rich phenomenology is intrinsically three-dimensional; however, the three-dimensional imaging of spin waves has so far not been possible. Here, we image the three-dimensional dynamics of spin waves excited in a synthetic antiferromagnet, with nanoscale spatial resolution and sub-ns temporal resolution, using time-resolved magnetic laminography.

Enhanced polarization switching characteristics of HfO ultrathin films via acceptor-donor co-doping.

In the realm of ferroelectric memories, HfO-based ferroelectrics stand out because of their exceptional CMOS compatibility and scalability. Nevertheless, their switchable polarization and switching speed are not on par with those of perovskite ferroelectrics. It is widely acknowledged that defects play a crucial role in stabilizing the metastable polar phase of HfO.

High-Pressure Synthesis of Semiconducting PbCuMnO with Near-Room-Temperature Ferrimagnetic Order.

A transition-metal oxide of PbCuMnO was prepared at 1523 K and 10 GPa. An A-site-ordered quadruple perovskite structure with the space group 3̅ is assigned for this compound. Based on bond-valence-sum calculations and X-ray absorption spectroscopy, the charge combination is determined to be PbCuMnO.

Amorphous-crystalline RuTi nanosheets enhancing OH species adsorption for efficient hydrogen oxidation catalysis.

Anion exchange membrane fuel cells are a potentially cost-effective energy conversion technology, however, the electrocatalyst for the anodic hydrogen oxidation reaction (HOR) suffers from sluggish kinetics under alkaline conditions. Herein, we report that Ru-based nanosheets with amorphous-crystalline heterointerfaces of Ru and Ti-doped RuO (a/c-Ru/Ti-RuO) can serve as a highly efficient HOR catalyst with a mass activity of 4.16 A mg, which is 19.

Pressure-tuned quantum criticality in the large-D antiferromagnet DTN.

Strongly correlated spin systems can be driven to quantum critical points via various routes. In particular, gapped quantum antiferromagnets can undergo phase transitions into a magnetically ordered state with applied pressure or magnetic field, acting as tuning parameters. These transitions are characterized by z = 1 or z = 2 dynamical critical exponents, determined by the linear and quadratic low-energy dispersion of spin excitations, respectively.

From Charge to Spin: An In-Depth Exploration of Electron Transfer in Energy Electrocatalysis.

Catalytic materials play crucial roles in various energy-related processes, ranging from large-scale chemical production to advancements in renewable energy technologies. Despite a century of dedicated research, major enduring challenges associated with enhancing catalyst efficiency and durability, particularly in green energy-related electrochemical reactions, remain. Focusing only on either the crystal structure or electronic structure of a catalyst is deemed insufficient to break the linear scaling relationship (LSR), which is the golden rule for the design of advanced catalysts.

Anomalous electrons in a metallic kagome ferromagnet.

Ordinary metals contain electron liquids within well-defined 'Fermi' surfaces at which the electrons behave as if they were non-interacting. In the absence of transitions to entirely new phases such as insulators or superconductors, interactions between electrons induce scattering that is quadratic in the deviation of the binding energy from the Fermi level. A long-standing puzzle is that certain materials do not fit this 'Fermi liquid' description.

Discovery of orbital ordering in BiSrCaCuO.

The primordial ingredient of cuprate superconductivity is the CuO unit cell. Theories usually concentrate on the intra-atom Coulombic interactions dominating the 3d and 3d configurations of each copper ion. However, if Coulombic interactions also occur between electrons of the 2p orbitals of each planar oxygen atom, spontaneous orbital ordering may split their energy levels.

Chemical Bonding Induces One-Dimensional Physics in Bulk Crystal BiIrSe.

One-dimensional (1D) systems persist as some of the most interesting because of the rich physics that emerges from constrained degrees of freedom. A desirable route to harness the properties therein is to grow bulk single crystals of a physically three-dimensional (3D) but electronically 1D compound. Most bulk compounds which approach the electronic 1D limit still field interactions across the other two crystallographic directions and, consequently, deviate from the 1D models.

Achieving Compatible p/n-Type Half-Heusler Compositions in Valence Balanced/Unbalanced MgVNiSb.

In thermoelectric and other inorganic materials research, the significance of half-Heusler (HH) compositions following the 18-electron rule has drawn interest in developing and exploiting the potential of intermetallic compounds. For the fabrication of thermoelectric modules, in addition to high-performance materials, having both p- and n-type materials with compatible thermal expansion coefficients is a prerequisite for module development. In this work, the p-type to n-type transition of valence balanced/unbalanced HH composition of MgVNiSb was demonstrated by changing the Mg:V chemical ratio.

Chiral-Induced Spin Selectivity Modulated Time-Correlated Single-Photon Counting for DNA Hybridization Detection.

The chiral-induced spin selectivity (CISS) effect can distinguish between the spin of electrons as they pass through chiral molecules by backscattering one of the spin components. Herein, we explore the role of the CISS effect in time-correlated single-photon counting measurements to detect DNA hybridization. We observe that the average lifetime of optical excited states of quantum dots attached to double-stranded DNA (dsDNA) varies with directions of the applied magnetic field.

Determination of optimal experimental conditions for accurate 3D reconstruction of the magnetization vector via XMCD-PEEM.

This work presents a detailed analysis of the performance of X-ray magnetic circular dichroism photoemission electron microscopy (XMCD-PEEM) as a tool for vector reconstruction of magnetization. For this, 360° domain wall ring structures which form in a synthetic antiferromagnet are chosen as the model to conduct the quantitative analysis. An assessment is made of how the quality of the results is affected depending on the number of projections that are involved in the reconstruction process, as well as their angular distribution.

Tunable positions of Weyl nodes via magnetism and pressure in the ferromagnetic Weyl semimetal CeAlSi.

The noncentrosymmetric ferromagnetic Weyl semimetal CeAlSi with simultaneous space-inversion and time-reversal symmetry breaking provides a unique platform for exploring novel topological states. Here, by employing multiple experimental techniques, we demonstrate that ferromagnetism and pressure can serve as efficient parameters to tune the positions of Weyl nodes in CeAlSi. At ambient pressure, a magnetism-facilitated anomalous Hall/Nernst effect (AHE/ANE) is uncovered.

Facilitating alkaline hydrogen evolution reaction on the hetero-interfaced Ru/RuO through Pt single atoms doping.

Exploring an active and cost-effective electrocatalyst alternative to carbon-supported platinum nanoparticles for alkaline hydrogen evolution reaction (HER) have remained elusive to date. Here, we report a catalyst based on platinum single atoms (SAs) doped into the hetero-interfaced Ru/RuO support (referred to as Pt-Ru/RuO), which features a low HER overpotential, an excellent stability and a distinctly enhanced cost-based activity compared to commercial Pt/C and Ru/C in 1 M KOH. Advanced physico-chemical characterizations disclose that the sluggish water dissociation is accelerated by RuO while Pt SAs and the metallic Ru facilitate the subsequent H* combination.

Orbital Origin of the Intrinsic Planar Hall Effect.

Recent experiments reported an antisymmetric planar Hall effect, where the Hall current is odd in the in plane magnetic field and scales linearly with both electric and magnetic fields applied. Existing theories rely exclusively on a spin origin, which requires spin-orbit coupling to take effect. Here, we develop a general theory for the intrinsic planar Hall effect (IPHE), highlighting a previously unknown orbital mechanism and connecting it to a band geometric quantity-the anomalous orbital polarizability (AOP).

Flexible metallic core-shell nanostructured electrodes for neural interfacing.

Electrodes with nanostructured surface have emerged as promising low-impedance neural interfaces that can avoid the charge-injection restrictions typically associated to microelectrodes. In this work, we propose a novel approximation, based on a two-step template assisted electrodeposition technique, to obtain flexible nanostructured electrodes coated with core-shell Ni-Au vertical nanowires. These nanowires benefit from biocompatibility of the Au shell exposed to the environment and the mechanical properties of Ni that allow for nanowires longer and more homogeneous in length than their only-Au counterparts.

Insights into the Effect of Charges on Hydrogen Bonds.

Previous computational and experimental studies showed that charges located at the surroundings of hydrogen bonds can exert two opposite effects on them: rupture or strengthening of the hydrogen bond. This work aims to generalize the effect of charges in different hydrogen-bonded systems and to propose a coherent explanation of this effect. For these purposes, 19 systems with intra- and intermolecular hydrogen bonds were studied computationally with DFT.