Investigating skyrmion stability and core polarity reversal in NdMnGe.

We present a study on nanoscale skyrmionic spin textures in [Formula: see text], a rare-earth complex noncollinear ferromagnet. We confirm, using X-ray microscopy, that [Formula: see text] can host lattices of metastable skyrmion bubbles at room temperature in the absence of a magnetic field, after applying a suitable field cooling protocol. The skyrmion bubbles are robust against temperature changes from room temperature to 330 K.

Steering perovskite precursor solutions for multijunction photovoltaics.

Multijunction photovoltaics (PVs) are gaining prominence owing to their superior capability of achieving power conversion efficiencies (PCEs) beyond the radiative limit of single-junction cells, where improving narrow bandgap tin-lead perovskites is critical for thin-film devices. With a focus on understanding the chemistry of tin-lead perovskite precursor solutions, we herein find that Sn(II) species dominate interactions with precursors and additives and uncover the exclusive role of carboxylic acid in regulating solution colloidal properties and film crystallisation, and ammonium in improving film optoelectronic properties. Materials that combine these two function groups, amino acid salts, considerably improve the semiconducting quality and homogeneity of perovskite films, surpassing the effect of the individual functional groups when introduced as part of separate molecules.

Realizing Strong and Robust Quasi-1D Superconductors via Multiorbital Chains: NaBe as an Example.

Quasi-one-dimensional (Q1D) systems are inherently unfavorable for superconductivity due to electronic instabilities and significant quantum fluctuations. This has led to a half-century-long pursuit of strong and robust Q1D superconductors. Herein, we propose an effective multiorbital chain approach that utilizes the interorbital self-doping to not only suppress the instability but also to position the Fermi level near the band edges.

In-Plane Anomalous Hall Effect Associated with Orbital Magnetization: Measurements of Low-Carrier Density Films of a Magnetic Weyl Semimetal.

For over a century, the Hall effect, a transverse effect under an out-of-plane magnetic field or magnetization, has been a cornerstone for magnetotransport studies and applications. Modern theoretical formulation based on the Berry curvature has revealed the potential that even an in-plane magnetic field can induce an anomalous Hall effect, but its experimental demonstration has remained difficult due to its potentially small magnitude and strict symmetry requirements. Here, we report observation of the in-plane anomalous Hall effect by measuring low-carrier density films of magnetic Weyl semimetal EuCd_{2}Sb_{2}.

Enhancement of the thermoelectric figure of merit in the Dirac semimetal CdAs by band-structure and -filling control.

Topological materials attract a considerable research interest because of their characteristic band structure giving rise to various new phenomena in quantum physics. Besides this, they are tempting from a functional materials point of view: Topological materials bear potential for an enhanced thermoelectric efficiency because they possess the required ingredients, such as intermediate carrier concentrations, large mobilities, heavy elements etc. Against this background, this work reports an enhanced thermoelectric performance of the topological Dirac semimetal CdAs upon alloying the trivial semiconductor ZnAs.

Anti-Poiseuille flow by spin Hall effect.

Hydrodynamics is known to emerge in electron flow when the electron-electron interaction dominates over the other momentum-nonconserving scatterings. The hydrodynamic equation that describes the electric current includes viscosity, extending beyond the Ohmic flow. The laminar flow of such a viscous electron fluid in a sample with finite width is referred to as the Poiseuille flow, where the flow velocity is maximum at the center and decreases towards the edges of the sample.

Spontaneous Hall effect induced by collinear antiferromagnetic order at room temperature.

Magnetic information is usually stored in ferromagnets, where the ↑ and ↓ spin states are distinguishable due to time-reversal symmetry breaking. These states induce opposite signs of the Hall effect proportional to magnetization, which is widely used for their electrical read-out. By contrast, conventional antiferromagnets with a collinear antiparallel spin configuration cannot host such functions, because of symmetry (time-reversal followed by translation t symmetry) and lack of macroscopic magnetization.

Bypassing the lattice BCS-BEC crossover in strongly correlated superconductors through multiorbital physics.

Superconductivity emerges from the spatial coherence of a macroscopic condensate of Cooper pairs. Increasingly strong binding and localization of electrons into these pairs compromises the condensate's phase stiffness, thereby limiting critical temperatures - a phenomenon known as the BCS-BEC crossover in lattice systems. In this study, we demonstrate enhanced superconductivity in a multiorbital model of alkali-doped fullerides (AC) that goes beyond the limits of the lattice BCS-BEC crossover.

Anisotropic exchange interaction of two hole-spin qubits.

Semiconductor spin qubits offer the potential to employ industrial transistor technology to produce large-scale quantum computers. Silicon hole spin qubits benefit from fast all-electrical qubit control and sweet spots to counteract charge and nuclear spin noise. However, the demonstration of a two-qubit interaction has remained an open challenge.

Antiferromagnetic spin-torque diode effect in a kagome Weyl semimetal.

Spintronics based on ferromagnets has enabled the development of microwave oscillators and diodes. To achieve even faster operation, antiferromagnets hold great promise despite their challenging manipulation. So far, controlling antiferromagnetic order with microwave currents remains elusive.

Designing giant Hall response in layered topological semimetals.

Noncoplanar magnets are excellent candidates for spintronics. However, such materials are difficult to find, and even more so to intentionally design. Here, we report a chemical design strategy that allows us to find a series of noncoplanar magnets-LnSn (Ln = Dy, Tb)-by targeting layered materials that have decoupled magnetic sublattices with dissimilar single-ion anisotropies and combining those with a square-net topological semimetal sublattice.

Spin-Orbit Coupling Driven Magnetic Response in Altermagnetic RuO.

The recent prediction of the new magnetic class, altermagnetism, has drawn considerable interest, fueled by its potential to host novel phenomena and to be utilized in next-generation spintronics devices. Among many promising candidates, rutile RuO is a prototypical candidate for realizing the prospects of altermagnetism. However, the experimental studies on RuO are still in the early stages.

Catalytic Synergy between Pd Nanoclusters and Ligand-Functionalized Layered Silicates for Improved Formic Acid Dehydrogenation.

The synthesis and stabilization of Pd nanoclusters on a support, as well as simultaneously achieving optimal catalytic activity, remain challenging tasks. Functionalizing the support surface with specific ligands offers a promising solution, but it often requires carefully balancing trade-offs between the reaction yield and catalyst stability. Here, we used two different ligands (propylamine and propylthiol) to functionalize the layered silicate's interlayer surface for Pd nanocluster synthesis and stabilization.

Strongly enhanced shift current at exciton resonances in a noncentrosymmetric wide-gap semiconductor.

Excitons are fundamental quasiparticles that are ubiquitous in photoexcited semiconductors and insulators. Despite causing a sharp and strong photoabsorption near the interband absorption edge, charge-neutral excitons do not yield photocurrent in conventional photovoltaic processes unless dissociated into free charge carriers. Here, we experimentally demonstrate that excitons can directly contribute to photocurrent generation through a nonlinear light-matter interaction in a noncentrosymmetric semiconductor CuI.

Thermomagnetic Anomalies by Magnonic Criticality in Ultracold Atomic Transport.

We investigate thermomagnetic transport in an ultracold atomic system with two ferromagnets linked via a magnetic quantum point contact. Using the nonequilibrium Green's function approach, we show a divergence in spin conductance and a slowing down of spin relaxation that manifest in the weak effective-Zeeman-field limit. These anomalous spin dynamics result from the magnonic critical point at which magnons become gapless due to spontaneous magnetization.

Development of ultrafast four-dimensional precession electron diffraction.

Ultrafast electron diffraction/microscopy technique enables us to investigate the nonequilibrium dynamics of crystal structures in the femtosecond-nanosecond time domain. However, the electron diffraction intensities are in general extremely sensitive to the excitation errors (i.e.

Nonlinear edge transport in a quantum Hall system.

Nonlinear transport phenomena in condensed matter reflect the geometric nature, quantum coherence, and many-body correlation of electronic states. Electric currents in solids are classified into (i) ohmic current, (ii) supercurrent, and (iii) geometric or topological current. While the nonlinear current-voltage (-) characteristics of the former two categories have been extensive research topics recently, those of the last category remains unexplored.

Ferroelectric Smectic C Liquid Crystal Phase with Spontaneous Polarization in the Direction of the Director.

In the previous study, the existence of an unidentified ferroelectric smectic phase is demonstrated in the low-temperature region of the ferroelectric smectic A phase, where the layer spacing decreases with decreasing temperature. In the present study, the phase is identified by taking 2D X-ray diffraction images of a magnetically oriented sample while allowing it to rotate and constructed a 3D reciprocal space with the sample rotation angle as the third axis for the whole picture of the reciprocal lattice vectors originating from the smectic structure. Consequently, circular diffraction images are obtained when the reciprocal lattice vectors are evenly distributed on the conical surface at a certain inclination angle in the reciprocal space.

Gate-Controlled Potassium Intercalation and Superconductivity in Molybdenum Disulfide.

Intercalation of guest ions into a van der Waals (vdW) gap in layered materials is a powerful route to create novel material phases and functionalities. Ionic gating is a technique to control the motions and configuration of ions for both intercalation and surface electrostatic doping. The advance of ionic gating enables the probe of dynamics of ion diffusion, carrier doping, and transport properties.

Selective Control of Electric Charge of Weyl Fermions in Pyrochlore Iridates.

Weyl fermions can exhibit exotic phenomena due to their magnetic charge in momentum space, while Weyl nodes are usually located away from Fermi energy, which forms electron or hole pockets as the electric charges. Previous studies have mostly focused on the magnetic charge, however, the electric charges are rarely explored. Here, the intriguing Hall responses arising from the interplay between magnetic and electric charges of Weyl fermions in pyrochlore iridates are reported.

Exotic Spin Excitations in a Polar Magnet VOSe_{2}O_{5}.

Magnetic resonance dynamics has been studied for a polar magnet VOSe_{2}O_{5}, which hosts several nontrivial magnetic phases including Néel-type skyrmion lattice (SkL). In both cycloidal and SkL spin states, two excitation modes active to oscillating magnetic field B_{ν}⊥c and one mode active to B_{ν}∥c are identified. The subsequent micromagnetic simulations well reproduce the observed selection rules and relative resonance frequencies, which allows the unambiguous assignment of the spin oscillation manner for each mode.