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High-cadence, multiwavelength observations have continuously revealed the diversity of tidal disruption events (TDEs), thus greatly advancing our knowledge and understanding of TDEs. In this work, we conducted an intensive optical-UV and X-ray follow-up campaign of TDE AT 2023lli and found a remarkable month-long bump in its UV/optical light curve nearly 2 months prior to maximum brightness. The bump represents the longest separation time from the main peak among known TDEs to date. The main UV/optical outburst declines as t ^−4.10 , making it one of the fastest-decaying optically selected TDEs. Furthermore, we detected sporadic X-ray emission 30 days after the UV/optical peak, accompanied by a reduction in the period of inactivity. It is proposed that the UV/optical bump could be caused by the self-intersection of the stream debris, whereas the primary peak is generated by the reprocessed emission of the accretion process. In addition, our results suggest that episodic X-ray radiation during the initial phase of decline may be due to the patched obscurer surrounding the accretion disk, a phenomenon associated with the inhomogeneous reprocessing process. The double TDE scenario, in which two stars are disrupted in sequence, is also a possible explanation for producing the observed early bump and main peak. We anticipate that the multicolor light curves of TDEs, especially in the very early stages, and the underlying physics can be better understood in the near future with the assistance of dedicated surveys such as the deep high-cadence survey of the 2.5 m Wide Field Survey Telescope.

Extracting precise stellar labels is crucial for large spectroscopic surveys like the Sloan Digital Sky Survey (SDSS) and APOGEE. In this paper, we report the newest implementation of StellarGAN, a data-driven method based on generative adversarial networks (GANs). Using 1D operators like convolution, the 2D GAN is modified into StellarGAN. This allows it to learn the relevant features of 1D stellar spectra without needing labels for specific stellar types. We test the performance of StellarGAN on different stellar spectra trained on SDSS and APOGEE data sets. Our result reveals that StellarGAN attains the highest overall F1-score on SDSS data sets (F1-score = 0.82, 0.77, 0.74, 0.53, 0.51, 0.61, and 0.55, for O-type, B-type, A-type, F-type, G-type, K-type, and M-type stars) when the signal-to-noise ratio (S/N) is low (90% of the spectra have an S/N < 50), with 1% of labeled spectra used for training. Using 50% of the labeled spectral data for training, StellarGAN consistently demonstrates performance that surpasses or is comparable to that of other data-driven models, as evidenced by the F1-scores of 0.92, 0.77, 0.77, 0.84, 0.84, 0.80, and 0.67. In the case of APOGEE (90% of the spectra have an S/N < 500), our method is also superior regarding its comprehensive performance (F1-score = 0.53, 0.60, 0.56, 0.56, and 0.78 for A-type, F-type, G-type, K-type, and M-type stars) with 1% of labeled spectra for training, manifesting its learning ability out of a limited number of labeled spectra. Our proposed method is also applicable to other types of data that need to be classified (such as gravitational-wave signals, light curves, etc.).

Recent studies have shown that the anisotropy is of great value to decipher cosmic rays’ origin and propagation. We have built a unified scenario to describe the observations of the energy spectra and the large-scale anisotropy and called attention to their synchronous evolution with energy. In this work, the impact of the local regular magnetic field (LRMF) and corresponding anisotropic diffusion on large-scale anisotropy have been investigated. When the perpendicular diffusion coefficient is much smaller than the parallel one, the dipole anisotropy points to the LRMF and the observational phase below 100 TeV could be reproduced. Moreover, we find that the dipole phase above 100 TeV strongly depends on the evolution of local diffusion. But the current measurements at that energy are still scarce. We suggest that more precise measurements at that energy could be carried out to unveil the local diffusion and further the local turbulence.

DFT + U is a widely used treatment in the density functional theory (DFT) to deal with correlated materials that contain open-shell elements, whereby the quantitative and sometimes even qualitative failures of local and semi-local approximations can be corrected without much computational overhead. However, finding appropriate U parameters for a given system and structure is non-trivial and computationally intensive, because the U value has generally a strong chemical and structural dependence. In this work, we address this issue by building a machine learning (ML) model that enables the prediction of material- and structure-specific U values at nearly no computational cost. Using Mn–O system as an example, the ML model is trained by calibrating DFT + U electronic structures with the hybrid functional results of more than 3000 structures. The model allows us to determine an accurate U value (MAE = 0.128 eV, R ^2 = 0.97) for any given Mn–O structure. Further analysis reveals that M–O bond lengths are key local structural properties in determining the U value. This approach of the ML U model is universally applicable, to significantly expand and solidify the use of the DFT + U method.

In the era of escalating climate change, understanding human impacts on marine heatwaves (MHWs) becomes essential. This study harnesses climate model historical and single forcing simulations to delve into the individual roles of anthropogenic greenhouse gases (GHGs) and aerosols in shaping the characteristics of global MHWs over the past several decades. The results suggest that GHG variations lead to longer-lasting, more frequent, and intense MHWs. In contrast, anthropogenic aerosols markedly curb the intensity and growth of MHWs. Further analysis of the sea surface temperature (SST) probability distribution reveals that anthropogenic GHGs and aerosols have opposing effects on the tails of the SST probability distribution, causing the tails to expand and contract, respectively. Climate extremes such as MHWs are accordingly promoted and reduced. Our study underscores the significant impacts of anthropogenic GHGs and aerosols on MHWs, which go far beyond the customary concept that these anthropogenic forcings modulate climate extremes by shifting global SST probabilities via modifying the mean-state SST.

Multi-messenger anomalies, including spectral hardening or excess of nuclei, leptons, ratios of $\bar{p}/p$ and B/C, and anisotropic reversal, have been observed in past years. The AMS-02 experiment also revealed different spectral breaks for positrons and electrons at 284 GeV and beyond tera electron volts, respectively. It is natural to ask whether all those anomalies originate from one unified physical scenario. In this work, the spatially dependent propagation (SDP) with a nearby supernova remnant (SNR) source is adopted to reproduce the abovementioned anomalies. There possibly exists a dense molecular cloud (DMC) around SNRs and the secondary particles can be produced by pp collision or fragmentation between the accelerated primary cosmic rays and DMC. As a result, the spectral hardening for primary and secondary particles and ratios of B/C and $\bar{p}/p$ can be well reproduced. Due to the energy loss at the source age of 330 kyr, the characteristic spectral break-off for a primary electron is at about 1 TeV as hinted at by the measurements. The secondary positrons and electrons from charged pion take up 5% of energy from their mother particles, so the positron spectrum has a break-off at ∼250 GeV. Therefore, the different spectral breaks for positrons and electrons together with other anomalies can be fulfilled in this unified physical scenario. More interesting is that we also obtain the featured structures as spectral break-offs at 5 TeV for secondary particles of Li, Be, and B, which can be used to verify our model. We hope that those tagged structures can be observed by the new generation of spaceborne experiment HERD in the future.

We report a superhumps analysis of seven SU UMa-type dwarf novae based on observations made by the Transiting Exoplanet Survey Satellite (TESS). Superhumps are seen during the superoutbursts of SU UMa-type dwarf novae. The monthlong data sets of TESS are well suited for studying the variations of superhumps. We selected seven non-eclipsing SU UMa-type dwarf novae with superhumps in which TESS light curves are available and have not yet been studied. The A, B, and C stages of superhumps in superoutbursts were determined by the O − C method. The results indicate that not all complete superoutbursts show three obvious stages, such as DT Oct and the second superoutburst of J1730+6247. We calculated the superhump period for each stage and the mean period for all superoutbursts. Taking the stage A superhump method, the mass ratio (M2/M1) was estimated. According to the results, the seven stars are pre-bounce systems with mass ratios ranging from 0.1 to 0.2. By combining the orbital periods and the mean superhump periods, the precession periods were calculated. The results show that the precession periods of the seven SU UMa stars are about 2 days.

The porosity of the micro-arc oxidation coating of pure titanium was assessed through the utilization of Mercury intrusion porosimetry (MIP). The porosity values were subsequently adjusted by accounting for the proportion of coating volume, resulting in a more precise determination of the coating’s porosity. Additionally, the fractal dimension of the pore structure was determined through the application of a linear regression equation utilizing the Mercury intrusion data. The findings indicate that the observed numerical dispersion from image metohd is substantial, with a range of 34.9% between the minimum and maximum values. This suggests that the precision and validity of the porosity outcomes derived from this approach are inadequate; The MIP is capable of determining both the porosity, average pore size and pore size distribution of the sample, while also mitigating the impact of the matrix through test result correction, thereby yielding precise porosity values. Additionally, the results of the verification experiment demonstrate a positive correlation between the porosity alteration of the MIP and oxidation duration, thereby affirming the reliability of the test outcomes; Through the analysis of pressure, pore size, cumulative Mercury intrude volume, and incremental Mercury intrude volume data obtained from MIP, the fractal dimension of the coating’s pore structure then be determined. Research showed that as the oxidation time increases, the pore fractal dimension of the MAO coating gradually expands within a narrow range, from 2.57 and finally stabilized at 2.77, indicating a gradual increase in pore structure complexity.

Organic sodium-ion batteries (OSIBs) using eco-friendly organic materials as electrodes have recently received much attention. However, the practical applications of OSIBs are generally limited by the inherent disadvantages of organic electrodes, such as their low conductivity, poor stability, and high solubility in electrolytes. Herein, we presented [5, 10, 15, 20-tetrathienylporphinato] M (II) (MTTP, M=2H, Ni) as new electrode materials in sodium-organic batteries. The incorporation of thiophene functionalized groups and nickel (Ⅱ) ion in the molecular design of porphyrins enabled stable and excellent electrochemical performance in sodium storage systems. Benefiting from multiple charge storage sites and bipolar characteristics, the NiTTP anode has a reversible capacity of 434 mAh g ^−1 at a current density of 25 mA g ^−1 . An excellent long-term cycling stability and high average voltage were obtained when NiTTP was used as a cathode. In a symmetrical battery, where NiTTP was used as both cathode and anode materials, a high average voltage of 2.3 V and a practical energy density of 93 Wh kg ^−1 was achieved. These results suggest that the thiophene-based porphyrin derivatives would be promising electrode materials for long-term organic sodium ion batteries for green and stable energy storage.

Xonotlite, as a multifunctional inorganic material, has been widely used in the fields of building insulation, friction braking, and bionic composite materials. However, the main method of producing xonotlite, the dynamic hydrothermal method, is regarded as a black box process. Optimization of synthesis conditions can only be achieved through trial-and-error experimentations, and there are inconsistencies in the experimental results reported in the literature. In this work, we established a thermodynamic model of the Ca(OH) _2 -SiO _2 -H _2 O system under hydrothermal conditions, and investigated influencing factors of the xonotlite synthesis. The results show that, the predicted lowest temperature of xonotlite synthesis is approximately 170 °C. Furthermore, an optimum condition to synthesis xonotlite with a purity of 99% is proposed as follows: reaction temperature, 200 °C; Ca/Si ratio, 0.9–1.0; water-solid ratio, no more than 20; pH, 7–8. This new synthesis process has been confirmed by experiments.

Magnetocaloric hydrogen liquefaction could be a ‘game-changer’ for liquid hydrogen industry. Although heavy rare-earth based magnetocaloric materials show strong magnetocaloric effects in the temperature range required by hydrogen liquefaction (77–20 K), the high resource criticality of the heavy rare-earth elements is a major obstacle for upscaling this emerging liquefaction technology. In contrast, the higher abundances of the light rare-earth elements make their alloys highly appealing for magnetocaloric hydrogen liquefaction. Via a mean-field approach, it is demonstrated that tuning the Curie temperature ( T _C ) of an idealized light rare-earth based magnetocaloric material towards lower cryogenic temperatures leads to larger maximum magnetic and adiabatic temperature changes (Δ S _T and Δ T _ad ). Especially in the vicinity of the condensation point of hydrogen (20 K), Δ S _T and Δ T _ad of the optimized light rare-earth based material are predicted to show significantly large values. Following the mean-field approach and taking the chemical and physical similarities of the light rare-earth elements into consideration, a method of designing light rare-earth intermetallic compounds for hydrogen liquefaction is used: tuning T _C of a rare-earth alloy to approach 20 K by mixing light rare-earth elements with different de Gennes factors. By mixing Nd and Pr in Laves phase (Nd, Pr)Al _2 , and Pr and Ce in Laves phase (Pr, Ce)Al _2 , a fully light rare-earth intermetallic series with large magnetocaloric effects covering the temperature range required by hydrogen liquefaction is developed, demonstrating a competitive maximum effect compared to the heavy rare-earth compound DyAl _2 .

Deterministic positioning single site-controlled high symmetric InGaAs quantum dots (QDs) in (111)B-oriented GaAs photonic crystal cavities with nanometer-scale accuracy provides an idea component for building integrated quantum photonic circuits. However, it has been a long-standing challenge of improving cavity Q -factors in such systems. Here, by optimizing the trade-off between the cavity loss and QD spectral quality, we demonstrate our site-controlled QD-nanocavity system operating in the intermediate coupling regime mediated by phonon scattering, with the dynamic coexistence of strong and weak coupling. The cavity-exciton detuning-dependent micro-photoluminescence spectrum reveals concurrence of a trend of exciton-polariton mode avoided crossing, as a signature of Rabi doublet of the strongly coupled system. Meanwhile, a trend of keeping constant or slight blue shift of coupled exciton–cavity mode(CM) energy across zero-detuning is ascribed to the formation of collective states mediated by phonon-assisted coupling, and their rare partial out-of-synchronization linewidth-narrowing is linked to their coexisting strong-weak coupling regime. We further reveal the pump power-dependent anti-bunching photon statistical dynamics of this coexisting strong-weak coupled system and the optical features of strongly confined exciton-polaritons, and dark-exciton-like states. These observations demonstrate the potential capabilities of site-controlled QD-cavity systems as deterministic quantum nodes for on-chip quantum information processing and provide guidelines for future device optimization for achieving the strong coupling regime.

The uneven residual stress caused by cold rolling on the raceway seriously affect the distortion and performance of bearing rings. Here, a novel strategy of electromagnetic shocking treatment (EST) was proposed to regulate the distribution of residual stress in the raceway of cold rolled M50 bearing ring. The results indicate that the distribution of residual stress and local micro-strain along the raceway of the cold rolled ring become more homogenized after EST, leading to the homogenization of hardness along the whole cross section. In addition, attributed to the ‘targeted’ regulation effect of EST without joule heat effect, the distribution of small angle grain boundaries and the texture also become uniform along the raceway.

Ba-enhanced stars are interesting probes of stellar astrophysics and Galactic formation history. In this work, we investigate the chemistry and kinematics of a large sample of Ba-enhanced ([Ba/Fe]>1.0) dwarf and subgiant stars with 5000 < T _eff < 6700 K from LAMOST. We find that both stellar internal evolution processes and external mass exchange due to binary evolution are responsible for the origins of the Ba enhancement of our sample stars. About one third of them exhibit C and N enhancement and an ultraviolet brightness excess, indicating they are products of binary evolution. The remaining Ba-enhanced stars with normal C and N abundances are mostly warm stars with T _eff > 6000 K. They are likely the consequences of stellar internal element transport processes, but they show very different element patterns to hotter Am/Fm stars. Our results reveal a substantially lack of high-[ α /Fe], Ba-enhanced stars in the [Fe/H]–[ α /Fe] plane, which we dub as a “high-[α/Fe] desert”. We suggest it is due to a lower efficiency for producing Ba-enhanced stars by low-mass asymptotic giant branch progenitors in binary systems. Our results call for detailed modeling of these Ba-enhanced stellar peculiarities, in the context of both stellar internal element transport and external mass accretion.

Non-centrosymmetric NdAlGe is considered to be a candidate for magnetic Weyl semimetal in which the Weyl nodes can be moved by magnetization. Clarification of the magnetic structures and couplings in this system is thus crucial to understand its magnetic topological properties. In this work, we conduct a systematical study of magnetic properties and critical behaviors of single-crystal NdAlGe. Angle-dependent magnetization exhibits strong magnetic anisotropy along the c -axis and absolute isotropy in the ab -plane. The study of critical behavior with H ∥ c gives critical exponents β = 0.236(2), γ = 0.920(1), and δ = 4.966(1) at critical temperature T _C = 5.2(2) K. Under the framework of the universality principle, M ( T , H ) curves are scaled into universality curves using these critical exponents, demonstrating reliability and self-consistency of the obtained exponents. The critical exponents of NdAlGe are close to the theoretical prediction of a tricritical mean-field model, indicating a field-induced tricritical behavior. Based on the scaling analysis, a H – T phase diagram for NdAlGe with H ∥ c is constructed, revealing a ground state with an up-up-down spin configuration. The phase diagram unveils multiple phases including up-up-down domains, up-up-down ordering state, polarized ferromagnetic (PFM), and paramagnetic (PM) phases, with a tricritical point (TCP) located at the intersection [ T _TCP = 5.27(1) K, H _TCP = 30.1(3) kOe] of up-up-down, PFM, and PM phases. The multiple phases and magnetic structures imply a delicate competition and balance between variable interactions and couplings, laying a solid foundation for unveiling topological properties and critical phenomena in this system.

Understanding the human water footprint and its impact on the hydrological cycle is essential to inform water management under climate change. Despite efforts in estimating irrigation water withdrawals in earth system models, uncertainties and discrepancies exist within and across modeling systems conditioned by model structure, irrigation parameterization, and the choice of input datasets. Achieving model reliability could be much more challenging for data-sparse regions, given limited access to ground truth for parameterization and validation. Here, we demonstrate the potential of utilizing remotely sensed vegetation and soil moisture observations in constraining irrigation estimation in the Noah-MP land surface model. Results indicate that the two constraints together can effectively reduce model sensitivity to the choice of irrigation parameterization by 7%–43%. It also improves the characterization of the spatial patterns of irrigation and its impact on evapotranspiration and surface soil moisture by correcting for vegetation conditions and irrigation timing. This study highlights the importance of utilizing remotely sensed soil moisture and vegetation measurements in detecting irrigation signals and correcting for vegetation growth. Integrating the two remote sensing datasets into the model provides an effective and less feature engineered approach to constraining the uncertainty of irrigation modeling. Such strategies can be potentially transferred to other modeling systems and applied to regions across the globe.

New major road infrastructure projects are planned or underway across sub-Saharan Africa (SSA) and are expected to have complex, and often deleterious, impacts on natural ecosystems across the region. For this reason, it is necessary to review evidence of how and through which mechanisms, roads might affect these landscapes. We reviewed 137 peer reviewed articles and documented 271 reported effects of roads and their underlying mechanisms inside and outside protected areas across SSA. Our findings show that (a) the study of the effects of roads on ecosystems in SSA is growing and not limited to the field of road ecology; (b) the negative effects of roads on species were reported at a similar frequency within and outside of protected areas; (c) the road-effect zone varied with effect but typically is between 1 and 7 km for larger mammals; (d) access to surrounding ecosystems through roads was the main mechanism driving effects; studies found accessibility influenced land use patterns and illegal hunting and harvesting; (e) other mechanisms by which roads affect (animal) species include, through functioning as a foraging site, and a habitat, and by acting as barriers to and corridors for movement; and (f) there was far more evidence on how roads can negatively impact ecosystems; in contrast, there was less certainty around mechanisms by which roads had no significant or a positive impact, since many of these were either speculated or unknown. An understanding of the underlying mechanisms can assist researchers and environmental assessment practitioners to predict how and where future road development might drive changes in biodiversity and land cover. Moving forward, we suggest that future research build a better understanding of the cumulative effects on different mammal and non-mammal communities and ecosystems more broadly and examine the socioeconomic contexts that characterize different road impacts in SSA.

The Bi _2 WO _6 and CuAlO _2 powders were synthesized through the method of solid-state reaction. This study prepared the newly and highly effective p–n type CuAlO _2 /Bi _2 WO _6 photocatalysts that had diverse CuAlO _2 compositions by employing an environmentally friendly and economical approach. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy(SEM), photoluminescence (PL) emission spectra, and UV–vis diffuse reflectance spectroscopy were adopted to characterize the photocatalysts. The as-synthesized CuAlO _2 /Bi _2 WO _6 heterocatalyst was utilized to reduce toxic Cr (VI) ions into Cr (III) by means of photoreduction under visible light irradiation. When CuAlO _2 (1.0 wt.%)/Bi _2 WO _6 was used, the Cr (VI) photoreduction rate constant was 4.7 times as many as that of pure Bi _2 WO _6 . The study also investigated how the ball milling time and CuAlO _2 composition affected the performance of CuAlO _2 /Bi _2 WO _6 . In addition, the stability of composite was investigated. The results revealed that the high conductivity of CuAlO _2 , excellent crystalline quality, and the p–n heterojunction between CuAlO _2 and Bi _2 WO _6 exerted a vital role in enhancing the photoreduction performance. This work explores the design of other new heterocatalysts, especially the p–n type composites containing CuAlO _2 .

The ultralow carbon high silicon iron-based alloy (sample A) with a single ferrite matrix was prepared. The corrosion performance difference and mechanism between it and conventional high silicon cast iron (sample B) were systematically studied using optical microscope, scanning electron microscope, electric corrosion equipment, electrochemical corrosion workshop and atomic force microscope. The results show that the corrosion rate of ultralow carbon iron-based alloys was significantly lower than that of high-silicon cast iron. For example, the static corrosion rate after 310 h, the corrosion rate of sample A was 0.2399 g/(m ^2 · h), and the corrosion rate of sample B was 1.5159 g/(m ^2 · h). The potential difference of the substrate was significantly reduced. That is, the ultralow carbon iron-based alloy exhibits better corrosion resistance, which is mainly attributed to the denser passivation film formed on its surface. The results of microhardness show that the hardness of Sample A was higher than that of Sample B.

Tungsten (W)-doped copper molybdate (CuMo _1−x W _x O _4 , x = 0∼0.12) compounds were prepared by the sol-gel method. The effects of doping content on the phase transition behavior and dielectric properties of CuMo _1−x W _x O _4 (x = 0∼0.12) were investigated. X-ray diffraction and UV–vis diffuse reflectance spectroscopy clarified that W doping facilitated the transition of green α -phase to brown γ -phase. The chemical composition and structure of the CuMo _1−x W _x O _4 (x = 0∼0.12) were investigated by Fourier transform infrared (FT-IR) spectroscopy and Raman spectra. The dielectric spectra of CuMo _1−x W _x O _4 at −130 °C∼150 °C and the color-change of CuMo _0.94 W _0.06 O _4 at 20 °C∼50 °C illustrated that the phase-transition temperature moves toward high temperature with increasing W. The functional relationship between the electrical modulus M’ and the frequency (1 Hz∼10 MHz) indicated that there are two dielectric relaxation mechanisms for CuMo _1−x W _x O _4 , which correspond to the polarization relaxation caused by hopping motion of polaron at low-temperature region (R1) and the relaxation dominated by oxygen vacancies at high temperatures (R2). It has also been confirmed that the phase transition of relaxation type exists in CuMo _1−x W _x O _4 , and that R1 occurs in γ -phase and R2 occurs in α -phase. It is of great significance to establish the dielectric relationship between phase transition and relaxation. With the content of W, the intensity of relaxation peak and activation energy of R1 did not change too much, but the relaxation behavior of R2 was inhibited and the activation energy increased gradually. The above results show that dielectric spectra are an important discovery as a new method to study the phase transition of materials, and is conducive to exploring the motion state of micro-particles. The control of phase-transition temperature is of great significance for this thermochromic material as a temperature sensor.

In this work, the perovskite compounds La _1.5 A _0.5 NiO _4+ _δ (A = Ca, Sr or Ba), which is one kind of mixed ionic electronic conductors (MIEC) with perovskite structure, was explored as cathode materials for proton conducting solid oxide fuel cells (H-SOFCs). In order to understand how the size of A-site cations affects material properties, the electrical conductivity and the electrochemical performances of La _1.5 A _0.5 NiO _4+ _δ (A = Ca, Sr or Ba) were compared. The results are more interesting. In the middle temperature region (600 °C–700 °C), Ca doping is the best choice among the three alkaline earth elements. In the low temperature region (300 °C–600 °C), Sr-doped single cells Sr-doped single cells have better performance. However, Ba doping easily generates BaCO _3 impurities, which reduces the ion transmission capacity and increases the interface resistance, resulting in poor performance of the single cell. This work shows that La _1.5 A _0.5 NiO _4+ _δ (A = Ca and Sr) is the main cathode candidate material for H-SOFC.

Following the realization of Weyl semimetals in quantum electronic materials, classical wave analogues of Weyl materials have also been theorized and experimentally demonstrated in photonics and acoustics. Weyl points in elastic systems, however, have been a much more recent discovery. In this study, we report on the design of an elastic fully-continuum three-dimensional material that, while offering structural and load-bearing functionalities, is also capable of Weyl degeneracies and surface topologically-protected modes in a way completely analogous to its quantum mechanical counterpart. The topological characteristics of the lattice are obtained by ab initio numerical calculations without employing any further simplifications. The results clearly characterize the topological structure of the Weyl points and are in full agreement with the expectations of surface topological modes. Finally, full field numerical simulations are used to confirm the existence of surface states and to illustrate their extreme robustness towards lattice disorder and defects.

Two-dimensional layered YbNi _3 Al _9 exhibits a chiral helimagnetic ground state, which is a candidate for the field-modulated chiral magnetic soliton. In this work, the magnetism and critical phenomenon of YbNi _3 Al _9 are investigated. As H ⊥ c , a magnetic step with loop can be observed in the field-dependent magnetization, which may be corresponding to the possible chiral magnetic soliton phase transition. Based on the analysis of isothermal magnetization around T _C , the critical exponents are obtained as β = 0.1370(2), γ = 1.7955(4), and δ = 14.1043(7), which fulfill the Widom scaling relation and Rushbrooke’s law. Moreover, the obtained critical exponents are testified by the modified Arrott plot and scaling hypothesis. The critical exponents of YbNi _3 Al _9 are close to the theoretically prediction of 2D-Ising model with the spatial-dimensionality n = 2 and spin-dimensionality d = 1, indicating one-dimensional magnetic coupling in the two-dimensional framework. Based on universality scaling, we construct the detailed H – T phase diagram around the phase transition with H ⊥ c , which reveals that the field-induced magnetic transition for H ⊥ c is of the first-order type.