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The interaction between superconductivity and spin-polarized surface states of topological materials provides an exciting platform for the research and development of proximity induced coupling effects, Majorana fermions, spin valves, spintronics, etc. and so on. In this work, the inverse proximity effect observed exactly at the super conducting transition temperature of indium (3.5 K) demonstrates the complex interplay between robust 2D spin-polarized surface states observed in our (002n) oriented MoTe2 nanolayer sheets with that of superconducting states. Interestingly, our phenomenological model based on the Werthamer-Helfand-Hohenberg (WHH) model and Ginzburg–Landau formalism, invoked to validate the experimental observations, indicates a competition between superconductivity and topological order, marked by a close correspondence between the temperature of crossover (Tcr = 2.45 K) of their respective length scales, ξ and Lφ, and the saturation temperature in resistivity. [ABSTRACT FROM AUTHOR]

The interaction between superconductivity and spin-polarized surface states of topological materials provides an exciting platform for the research and development of proximity induced coupling effects, Majorana fermions, spin valves, spintronics, etc. and so on. In this work, the inverse proximity effect observed exactly at the super conducting transition temperature of indium (3.5 K) demonstrates the complex interplay between robust 2D spin-polarized surface states observed in our (002n) oriented MoTe2 nanolayer sheets with that of superconducting states. Interestingly, our phenomenological model based on the Werthamer-Helfand-Hohenberg (WHH) model and Ginzburg–Landau formalism, invoked to validate the experimental observations, indicates a competition between superconductivity and topological order, marked by a close correspondence between the temperature of crossover (Tcr = 2.45 K) of their respective length scales, ξ and Lφ, and the saturation temperature in resistivity. [ABSTRACT FROM AUTHOR]

Intrinsically broken symmetries in the bulk of topological insulators (TIs) are manifested in their surface states. Despite particle–hole asymmetry in TIs, it has often been assumed that their surface states are characterized by a particle–hole symmetric Dirac energy dispersion. In this work, we demonstrate that the effect of particle–hole asymmetry is essential to correctly describe the energy spectrum and the magneto-optical response in TIs thin-films. In thin-films of TIs with a substantial degree of particle–hole symmetry breaking, such as Sb 2 Te 3 , the longitudinal optical conductivity displays absorption peaks arising from optical transitions between bulk and surface Landau levels for low photon energies. The transition energies between the bulk and surface Landau levels exhibit clearly discernable signatures from those between surface Landau levels due to their distinct magnetic field dependence. Bulk contributions to the magneto-optical conductivity in a TI thin-film are enhanced via one type of doping while being suppressed by the other. This asymmetric dependence on the type of doping aids in revealing the particle–hole asymmetry in TI thin-films. [ABSTRACT FROM AUTHOR]

Circular photogalvanic effect (CPGE) of single-crystalline ternary topological insulator Bi 2 (Te 0.23 Se 0.77) 3 nanowires, which are synthesized by the chemical vapor deposition, have been investigated. It is demonstrated that the distributions of the elements in the nanowires are fairly uniform, and they have high crystal quality. Compared with Bi 2 Se 3 nanowires, the ternary Bi 2 (Te 0.23 Se 0.77) 3 nanowires have better responsivity to circularly polarized light. The incident angle dependence of the CPGE current indicates that the symmetry of the surface states of the nanowire belongs to C 3 v symmetry. The temperature dependence of the CPGE current is also investigated. As the temperature decreases from 300 to 77 K, the CPGE current first increases and then decreases, which is due to the variation of the mobility and photo-generated carrier density with temperature. Our work suggests that ternary Bi 2 (Te 1 − x Se x) 3 nanowires are good candidates for designing polarization-sensitive photoelectric devices. [ABSTRACT FROM AUTHOR]

Element doping can have a profound impact on the photoelectrochemical properties of quantum dots (QDs); nevertheless, the hitherto known information in this regard is mainly from the steady-state characterizations and remains lacking input from the dynamics perspective. Herein, we present a systematic scrutiny of the element doping-induced effects in Zn-doped CdTe QDs. By means of steady-state/time-resolved/temperature-dependent photoluminescence spectroscopy and ultrafast transient absorption spectroscopy, we reveal that the slight Zn-doping in CdTe QDs can greatly affect the involved carrier relaxation dynamics through a density-of-state modification for both near-band-edge and localized surface trap states. Furthermore, such slight doping is found to be quite significant in modulating the photoreduction efficiency (of particular relation to the localized surface trap states) as well as altering the involved relaxation/reaction activation energy and phonon effect in this QDs system. This work enriches our fundamental understanding of the element doping-induced surface/interface effects, from the dynamics perspective in particular, and, hence, offers helpful guidance for QDs-based photoelectrochemical design and optimization. [ABSTRACT FROM AUTHOR]

The Jackiw–Rebbi model is a relativistic quantum model credited with the theoretical predictions of zero-energy bound states and charge fractionalization prior to the discovery of topological insulators and the fractional quantum Hall effect. In this work, we demonstrate a photonic equivalent of the Jackiw–Rebbi model by resorting to photonic crystal band structure engineering. Specifically, our photonic realization employs two spatial inversion symmetric binary photonic crystals exhibiting complementary signs of differential effective mass parameter (δ m) for their second bandgaps. Their concatenation manifests a step discontinuity in the spatial profile of the effective mass parameter, forming a domain wall at the photonic crystal interface. Upon analyzing the reflectance spectra of the concatenated photonic crystal structure, we find a midgap surface state localized at this domain wall. Furthermore, much in agreement with the Jackiw–Rebbi zero-energy solution, the materialized photonic surface state also exhibits a zero-energy character in a differential energy space corresponding to the δ m parameter, which has been quantified experimentally. Crucially, the conceived zero-energy mode amounts to the observation of a peculiar surface state with polarization-indiscriminate dispersion that can help realize all-angle polarization neutral optics. [ABSTRACT FROM AUTHOR]

Spacecraft charging and electrostatic discharging (ESD) are prone to occur in harsh space environments. In particular, in the case of coupling strong electromagnetic field (EMF), ESD damages may occur at a low charging potential, posing a serious threat to on-orbit spacecraft missions. To investigate the mechanism and the pertinent suppression method for vacuum surface discharge induced by EMF, a specially-designed platform for EMF-induced surface discharge was set up. Surface structures with various spatial scales were created separately by using different surface engineering strategies, including direct fluorination, mechanical polishing, and 3D-printed grooving. The resulting surface physicochemical characteristics of the samples were examined. Furthermore, the surface discharge characteristics for different methods induced by strong EMF were systematically analyzed, considering the surface trap state distribution and secondary electron yield (SEY). The findings indicate that the proposed surface treatment methods demonstrate varying levels of improvement in mitigating EMF-induced discharge. Direct fluorination was found to produce lower SEY and to accelerate surface charge dissipation due to an elevated shallow trap density, making it favorable for suppressing the EMF-induced discharge. In addition, suitable surface roughness and groove size can effectively impede the development of the multipactor, thereby preventing EMF-induced discharge. This research is expected to provide valuable insights into the protection design of EMF-induced discharge on spacecraft. [ABSTRACT FROM AUTHOR]

In this paper, we present an active fault-tolerant, vehicle motion control, based on the multi-agent approach for a four-wheel independent steering system. This improves handling stability and active safety of the vehicle in the case of actuator faults. Firstly, an eight-degree-of-freedom four-input vehicle model is established by using the vector transformation method, which takes the four-wheel angle as the input and the yaw rate and the sideslip angle, obtained by the lateral force of a single wheel, as the outputs. Then, we established the topological structure of the four-wheel independent steering subsystems based on graph theory. Aiming at the known fault conditions, an adaptive sliding mode active fault-tolerant control based on the multi-agent four-wheel independent steering system is proposed, in which the unmodeled part of the system is estimated using adaptive methods. For unknown fault conditions, an active fault-tolerant control of the four-wheel independent steering system based on state observer is proposed. An extended state observer with sliding mode surface function as a state variable is designed to estimate actuator faults. Finally, it was demonstrated that the designed state observer and distributed active fault-tolerant control method reduced the impact of actuator failures on vehicle steering and improved the stability of the steering process based on the Lyapunov theory. The hardware in the loop experimental results validate the effectiveness of the proposed novel method. [ABSTRACT FROM AUTHOR]

This study deals with two different aspects of the high-strength low-alloyed 1100 MC steel. The first is associated with the remarkable heterogeneity (linked with surface decarburization) in the surface state produced during sheet rolling with respect to the sheet width. The variable thickness surface layer exhibits a microstructure different from that of the deeper bulk. Variation in the thickness of the thermally softened near-surface region strongly affects Barkhausen noise as well. This technique can be considered a reliable tool for monitoring the aforementioned heterogeneity. It can also be reported that the opposite sides of the sheet are different with respect to the surface state, the heterogeneity distribution, and the corresponding Barkhausen noise. These aspects indicate different conditions during hot rolling followed by rapid quenching on the upper and lower rollers. Furthermore, it was found that the degree of decarburizing and the corresponding surface heterogeneity is also a function of C content, and steels with lower C content exhibit less pronounced surface heterogeneity. The second aspect is related to the remarkable asymmetry in Barkhausen noise emission with respect to two consecutive bursts. This asymmetry is due to the presence of remnant magnetization in the sheet produced during manufacturing. The remnant magnetization is coupled to the magnetic field produced by the excitation coil of the Barkhausen noise sensor and strongly contributes to the aforementioned asymmetry. The remnant magnetization attenuates the domain wall mobility, which results in weaker Barkhausen noise. Moreover, the Barkhausen noise envelopes and the extracted features such as the position of the envelope maximum and its width are strongly affected by the remnant magnetization. Insufficient demagnetization makes the body magnetically softer and makes a wider range of magnetic fields in which Barkhausen noise emission can be detected. As soon as sufficient removal of this remnant magnetization is carried out in the vanishing magnetic field (demagnetization), the aforementioned remarkable asymmetry is fully lost. [ABSTRACT FROM AUTHOR]

Topological insulators exhibit great attraction in the fields of spintronics and quantum anomalous Hall effect, but their interaction with electromagnetic waves is rarely explored. Herein, topological insulator MnBi2Te4, synthesized via a solid-phase melting approach, was employed to compound with conductive materials. Benefiting from the unique topological untrivial property embodied in conductive topological surface state and ingenious composite microstructure, MnBi2Te4/carbon fibers displayed an efficient conductive network and high permittivity, obtaining an ultrathin electromagnetic wave absorption capacity with a maximum effective absorbing bandwidth of 2.6 GHz at 0.9 mm and a minimum reflection loss of −38.4 dB at 1.2 mm. More importantly, its effective absorbing peaks can cover 2–18 GHz through regulating its thickness, ranging from 0.8 to 6 mm. It is deciphered that topological insulators can retain the conductivity from conductive materials to a great extent and achieve distinct performances by compositing with materials of various microstructures. This work provides valuable insights into utilizing the unique advantages of topological insulators through compositing strategy and presents a precious approach for electromagnetic wave–absorbing composite materials. [ABSTRACT FROM AUTHOR]

The recently discovered superconductor UTe2 is a promising candidate for spin-triplet superconductors, but the symmetry of the superconducting order parameter remains highly controversial. Here, we determine the superconducting gap structure by the thermal conductivity of ultraclean UTe2 single crystals. We find that the a-axis thermal conductivity divided by temperature κ/T in zero-temperature limit is vanishingly small for both magnetic field H‖a and H‖c axes up to H/Hc2 ~ 0.2, demonstrating the absence of nodes around the a axis contrary to the previous belief. The present results, combined with the reduction of nuclear magnetic resonance Knight shift, indicate that the superconducting order parameter belongs to the isotropic Au representation with a fully gapped pairing state, analogous to the B phase of superfluid 3He. These findings reveal that UTe2 is likely to be a long-sought three-dimensional strong topological superconductor, hosting helical Majorana surface states on any crystal plane. [ABSTRACT FROM AUTHOR]

Topological insulators (TIs) are emerging materials for next-generation low-power nanoelectronic and spintronic device applications. TIs possess non-trivial spin-momentum locking features in the topological surface states in addition to the spin-Hall effect (SHE), and Rashba states due to high spin-orbit coupling (SOC) properties. These phenomena are vital for observing the charge-spin conversion (CSC) processes for spin-based memory, logic and quantum technologies. Although CSC has been observed in TIs by potentiometric measurements, reliable nonlocal detection has so far been limited to cryogenic temperatures up to T = 15 K. Here, we report nonlocal detection of CSC and its inverse effect in the TI compound Bi1.5Sb0.5Te1.7Se1.3 at room temperature using a van der Waals heterostructure with a graphene spin-valve device. The lateral nonlocal device design with graphene allows observation of both spin-switch and Hanle spin precession signals for generation, injection and detection of spin currents by the TI. Detailed bias- and gate-dependent measurements in different geometries prove the robustness of the CSC effects in the TI. These findings demonstrate the possibility of using topological materials to make all-electrical room-temperature spintronic devices. [ABSTRACT FROM AUTHOR]

The surface spin-polarized states in the electronic structure of Pt(111) and graphene/Pt(111) have been studied in detail using angle-resolved photoelectron spectroscopy and density functional theory calculations. The results obtained show the presence of cone-shaped surface states near the Fermi level in the vicinity of the point of the surface Brillouin zone of platinum for both systems. Theoretical calculations confirm that these states are spin-polarized surface states of Pt(111) single crystal. [ABSTRACT FROM AUTHOR]

Assessing the nature of topological quantum materials, and in particular probing the existence of topological surface states, is a very challenging task. Terahertz (THz) frequency scattering near‐field optical microscopy has emerged as an effective technique to investigate the presence of massless surface carriers by locally probing collective surface excitations, i.e., plasmon polaritons, whose dispersion critically depends on the density and nature of surface carriers. Here, thin (14–19 nm) films of Bi2Se3 are experimentally investigated through a combination of x‐ray diffraction, Hall‐bar magneto‐transport, and near‐field detectorless optical holography at THz frequencies, from 2 to 4.3 THz. The dispersion of surface plasmon polaritons are determined for different Bi2Se3 film thicknesses, proving the presence of massless surface carriers. The results open intriguing opportunities in THz nano‐plasmonics and topological nano‐photonics including the development of superlenses and metasurfaces, making use of plasmon polaritons. [ABSTRACT FROM AUTHOR]

The topological magnetoelectric effect (TME) is a hallmark response of the topological field theory, which provides a paradigm shift in the study of emergent topological phenomena. However, its direct observation is yet to be realized due to the demanding magnetic configuration required to gap all surface states. Here, we theoretically propose that axion insulators with a simple ferromagnetic configuration, such as the MnBi2Te4/(Bi2Te3)n family, provide an ideal playground to realize the TME. In the designed triangular prism geometry, all the surface states are magnetically gapped. Under a vertical electric field, the surface Hall currents give rise to a nearly half-quantized orbital moment, accompanied by a gapless chiral hinge mode circulating in parallel. Thus, the orbital magnetization from the two topological origins can be easily distinguished by reversing the electric field. Our work paves the way for direct observation of the TME in realistic axion-insulator materials. [ABSTRACT FROM AUTHOR]

We review recent progress in the electronic structure study of intrinsic magnetic topological insulators (MnBi2Te4) · (Bi2Te3)n (⁠|$n\ = \ 0,\ 1,\ 2,\ 3$|⁠) family. Specifically, we focus on the ubiquitously (nearly) gapless behavior of the topological Dirac surface state observed by photoemission spectroscopy, even though a large Dirac gap is expected because of surface ferromagnetic order. The dichotomy between experiment and theory concerning this gap behavior is perhaps the most critical and puzzling question in this frontier. We discuss various proposals accounting for the lack of magnetic effect on the topological Dirac surface state, which are mainly categorized into two pictures, magnetic reconfiguration and topological surface state redistribution. Band engineering towards opening a magnetic gap of topological surface states provides great opportunities to realize quantized topological transport and axion electrodynamics at higher temperatures. [ABSTRACT FROM AUTHOR]

Surface features are crucial for assessing welding quality because they serve as an intuitive depiction of the quality of the joint and have a major influence on welding strength. According to the characteristics of the refill friction stir spot welding (RFSSW) process and an analysis of the surface-state and internal morphology of RFSSW joints, a method of predicting the mechanical properties of RFSSW joints based on surface-state characteristics was proposed. In this paper, a laser-ranging sensor was used to characterize the surface state of RFSSW joints, and parametric characterization methods of the surface-state features of RFSSW joints were proposed. On this basis, a support vector machine was used to predict and analyze the fracture mode of RFSSW joints. The accuracy of the analysis of the test samples reached 95.8%. This paper provides a more efficient and convenient new method for the quality evaluation of RFSSW joints. [ABSTRACT FROM AUTHOR]

Machining INCONEL® presents significant challenges in predicting its behaviour, and a comprehensive experimental assessment of its machinability is costly and unsustainable. Design of Experiments (DOE) can be conducted non-destructively through Finite Element Analysis (FEA). However, it is crucial to ascertain whether numerical and constitutive models can accurately predict INCONEL® machining. Therefore, a comprehensive review of FEA machining strategies is presented to systematically summarise and analyse the advancements in INCONEL® milling, turning, and drilling simulations through FEA from 2013 to 2023. Additionally, non-conventional manufacturing simulations are addressed. This review highlights the most recent modelling digital solutions, prospects, and limitations that researchers have proposed when tackling INCONEL® FEA machining. The genesis of this paper is owed to articles and books from diverse sources. Conducting simulations of INCONEL® machining through FEA can significantly enhance experimental analyses with the proper choice of damage and failure criteria. This approach not only enables a more precise calibration of parameters but also improves temperature (T) prediction during the machining process, accurate Tool Wear (TW) quantity and typology forecasts, and accurate surface quality assessment by evaluating Surface Roughness (SR) and the surface stress state. Additionally, it aids in making informed choices regarding the potential use of tool coatings. [ABSTRACT FROM AUTHOR]

Microlens arrays, as typical micro-optical elements, effectively enhance the integration and performance of optical systems. The surface shape errors and surface roughness of microlens arrays are the main indicators of their optical characteristics and determine their optical performance. In this study, a mask-moving-projection-lithography-based high-precision surface fabrication method for microlens arrays is proposed, which effectively reduces the surface shape errors and surface roughness of microlens arrays. The pre-exposure technology is used to reduce the development threshold of the photoresist, thus eliminating the impact of the exposure threshold on the surface shape of the microlens. After development, the inverted air bath reflux method is used to bring the microlens array surface to a molten state, effectively eliminating surface protrusions. Experimental results show that the microlens arrays fabricated using this method had a root mean square error of less than 2.8%, and their surface roughness could reach the nanometer level, which effectively improves the fabrication precision for microlens arrays. [ABSTRACT FROM AUTHOR]

The realization of intrinsic magnetic topological insulators offers an ideal platform to investigate high-temperature quantum anomalous Hall effect as well as quantum devices. The family of MnBi2Te4(Bi2Te3)n has been confirmed that it belongs to this system. However, whether there is a bandgap in the surface states remains controversial. In this work, the ferromagnetism in Sb-doped MnBi4Te7 is confirmed by magnetic transport. Utilizing angle-resolved photoemission spectroscopy, we demonstrate the nontrivial topology in Mn(Bi0.7Sb0.3)4Te7 with an energy gap on the MnBi2Te4 termination. As well, we detect distinct topological surface states on two different terminations. Our results provide spectral evidence of an energy gap in the topological surface states. [ABSTRACT FROM AUTHOR]

The realization of intrinsic magnetic topological insulators offers an ideal platform to investigate high-temperature quantum anomalous Hall effect as well as quantum devices. The family of MnBi2Te4(Bi2Te3)n has been confirmed that it belongs to this system. However, whether there is a bandgap in the surface states remains controversial. In this work, the ferromagnetism in Sb-doped MnBi4Te7 is confirmed by magnetic transport. Utilizing angle-resolved photoemission spectroscopy, we demonstrate the nontrivial topology in Mn(Bi0.7Sb0.3)4Te7 with an energy gap on the MnBi2Te4 termination. As well, we detect distinct topological surface states on two different terminations. Our results provide spectral evidence of an energy gap in the topological surface states. [ABSTRACT FROM AUTHOR]

Large-scale brain activity mapping is important for understanding the neural basis of behaviour. Electrocorticograms (ECoGs) have high spatiotemporal resolution, bandwidth, and signal quality. However, the invasiveness and surgical risks of electrode array implantation limit its application scope. We developed an ultrathin, flexible shape-changing electrode array (SCEA) for large-scale ECoG mapping with minimal invasiveness. SCEAs were inserted into cortical surfaces in compressed states through small openings in the skull or dura and fully expanded to cover large cortical areas. MRI and histological studies on rats proved the minimal invasiveness of the implantation process and the high chronic biocompatibility of the SCEAs. High-quality micro-ECoG activities mapped with SCEAs from male rodent brains during seizures and canine brains during the emergence period revealed the spatiotemporal organization of different brain states with resolution and bandwidth that cannot be achieved using existing noninvasive techniques. The biocompatibility and ability to map large-scale physiological and pathological cortical activities with high spatiotemporal resolution, bandwidth, and signal quality in a minimally invasive manner offer SCEAs as a superior tool for applications ranging from fundamental brain research to brain-machine interfaces. The invasiveness of extensive craniotomy hinders large-scale cortex mapping. Here, the authors developed a flexible, shape-changing electrode array which enables minimally invasive implantation and achieves high spatiotemporal resolution brain mapping. [ABSTRACT FROM AUTHOR]

Retrieval studies document Ti‐6Al‐4V selective dissolution within crevices of total hip replacement devices. A gap persists in the fundamental understanding of Ti‐6Al‐4V crevice corrosion in vivo and its impact on local impedance. Previous studies use nearfield electrochemical impedance spectroscopy (nEIS) for characterization of retrieved CoCrMo surfaces and phase angle symmetry‐based EIS (sbEIS) for rapid data acquisition. In this study, these methods are combined with a deep neural network to characterize the local impedance changes after selective dissolution. It is hypothesized that structural changes occurring during dissolution will manifest as property changes to the oxide film capacitance. First, after sustained cathodic activation, the Ti‐6Al‐4V β phase selectively dissolves from the surface. Next, nEIS acquires n = 100 control and n = 105 dissolved spectra. Over dissolved regions, oxide capacitance significantly increases (Log10Q = ‐4.17 versus ‐4.78 (Scm−2(s)α), p = 0.000). Using single frequency EIS (5000 Hz), a capacitance‐based scanning impedance microscopy method identifies dissolved regions within seconds. Finally, Bode phase plots of the 205 control and dissolved nEIS spectra are input into a deep neural network. After training with n = 180 spectra, the model predicts the surface state for n = 25 previously unseen nEIS spectra with 96% accuracy. [ABSTRACT FROM AUTHOR]

The performance of magnonic devices such as converters, switches, and multiplexers greatly depends on magnonic noise. While a peculiar discrete magnonic noise has been previously reported, the sources of underlying magnon dynamics occurring in high-magnon density conditions have not been clarified. Here, zero-span measurements of the spectrum analyzer were recorded to accurately detect magnonic noise as a fluctuation of the spin-wave amplitude. The results of low-frequency magnonic noise demonstrated a spin-wave mode dependency, indicating the existence of a peculiar magnon surface state. Furthermore, the energy thresholds of four-magnon scattering and autooscillation were determined using magnonic white noise. The noise data obtained in this study can help promote theoretical and experimental research on magnons. Decoding Magnonic Noise: Peculiar Surface State Discovered in Spin-Wave Study This study examines magnonic noise, a variation in spin-wave amplitude, which could offer crucial data about carrier dynamics in magnonic devices. The researchers, headed by R.F. and K.S., utilized a method known as zero-span operation of a spectrum analyser (an instrument used to examine the spectral composition of electrical, acoustic, or optical waveform) to measure magnonic noise. The study showed that magnonic noise is sensitive to both surface and internal spin-wave turbulence. They also discovered that the noise measurements permitted the direct assessment of the energy thresholds of four-magnon scattering and auto-oscillation. The findings propose that magnonic noise measurements could be a potent tool in designing future magnonic devices. The study concludes that more research is needed to detect magnonic noise at low magnon density for more efficient magnonic device design. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author. Magnonic noise has unveiled magnon dynamics, including nonlinear scattering processes. [ABSTRACT FROM AUTHOR]

Compared to conventional Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF) and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF), BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ (BCFZY) with special surface species and structure can exhibit a distinctive compromise between the redox activity and cell stability. The X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD) and infrared spectrum (IR) results suggest that besides the oxygen species of BSCF and LSCF, the OH-related species can be detected on BCFZY, which can play a promoting role in oxygen catalysis activity. The O2− -conducting solid oxide fuel cell (SOFC) with BCFZY cathode shows the superior power densities at intermediate temperatures (750-650 °C), which are 1.2–1.6 times than those of BSCF cell, and 1.8–2.1 times than those of LSCF cell. Distribution of relaxation times (DRT) analysis on three symmetric cells and three single cells reveal that BCFZY cathode shows superior oxygen adsorption and dissociation, which can be ascribed to the peculiar OH-related species and multiscale structure on the surface. The cell with BCFZY cathode can remain the stable performance during the discharge testing at 650 °C for 240 h, indicating a reliable surface state to promote both oxygen catalysis activity as well as the performance stability for O2− -conducting SOFC. • BCFZY demonstrates considerable activity vs BSCF and LSCF on O2--conducting SOFC. • BCFZY cell achieves high power density (1.99–1.40 W cm−2) at 750-650 °C. • BCFZY cathode exhibits superior oxygen exchange processes on surface. • The special surface state of BCFZY cathode improves O 2 catalysis and stability. [ABSTRACT FROM AUTHOR]

Flexible ultraviolet (UV) photodetector exhibits a promising application in portable electronic gadgets, display devices and biomedical imaging. In this study, a flexible photoanode of the photoelectrochemical (PEC)-type UV photodetector based on rutile TiO2 nanowires (TiO2 NWs) grown on carbon fiber cloth is realized. In photovoltaic applications, an insulating layer is usually introduced to suppress interfacial recombination and reduce the surface trap states. The interfacial recombination of semiconductor/electrolyte is suppressed by coating an Al2O3 barrier layer on the TiO2 NWs. The photodetectors of the TiO2@Al2O3 NWs show stable photocurrent, a high light/dark current ratio (I light/ I dark) of 1170, a faster rise and decay response times of 0.09 and 0.09 s, and excellent spectral selectivity from 300 to 400 nm. The peak responsivity of the photodetectors reaches 2.8 mA W−1 at 360 nm. This flexible photoanode have a potential application in wearable PEC UV photodetector. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) is deemed one of the prominent energy solutions of the 21st century due to the significant scientific and technological efforts devoted to the realization of a renewable carbon-free H2-based economy. The generation of highly efficient clean H2 fuel from the electrocatalysis of earth-abundant water is one of the key aspects of sustainable clean energy technologies. Traditionally, Pt-based catalysts have demonstrated an efficient hydrogen evolution reaction (HER), but their scarcity and high cost hinder their commercial applications. Herein, we demonstrate a facile synthesis of the MnCo2S4 nanosheet catalyst that was successfully transformed from MnCo2O4 through an anion-exchange reaction. The electrochemical performance of MnCo2S4 is considerably superior compared to that of MnCo2O4, demonstrating low overpotentials of −111 and −233 mV (1 M KOH) and −124 and −323 mV (0.5 M H2SO4) at current densities of 10 and 500 mA cm−2, respectively, with a moderate Tafel slope of 63 mV dec−1. The optimized catalyst showed excellent sustainability for an ultralong H2 evolution up to 50 h at 10 and 100 mA cm−2 in both media and an admirable endurance in a voltage-step response at various current rates (10 to 100 mA cm−2). The post-stability XPS reveals the partial alteration of cobalt into a metallic state on the catalyst surface without a significant change in the surface topography. The outstanding HER performance is credited to the increased number of electrochemically active sites and enhanced electronic conductivity resulting from the conversion of the oxide phase into a sulfide phase through anion exchange. [ABSTRACT FROM AUTHOR]

β-Ga2O3 is an emerging ultra-wide bandgap semiconductor with wide-ranging applications from civil to military realms. Due to the varied surface states and upward band-bending of β-Ga2O3 with most metals, most of the conventional metal contacts turn out to be Schottky in nature, leading to a paucity of suitable Ohmic contacts to Ga2O3. Transparent conducting oxides (TCOs) offer the flexibility of conduction along with optical transparency, useful especially for optoelectronic devices. Herein, we report on the use of indium-zinc oxide (IZO), a TCO, as a suitable, unconventional contact to β-Ga2O3. The devices show a unique conversion from Schottky to Ohmic by annealing at an optimized temperature of 650 °C, while changing back to Schottky at higher temperatures. At 650 °C, the interface chemistry as studied by x-ray photoelectron spectroscopy changes drastically with band-bending of β-Ga2O3 shifting from upward to downward at the interface leading to a type II band alignment, responsible for the Schottky-to-Ohmic conversion. The results provide evidence of using IZO layer as an alternate contact material to β-Ga2O3 whose behavior as Ohmic or Schottky contact may be tuned by simply varying the annealing temperature and inducing interfacial changes at the semiconductor–electrode interface, while maintaining excellent device resilience. The proposed conducting oxide layer provides an effective strategy toward control and tunability in nature of contacts toward gallium oxide and its applications for high temperature resilience solar-blind photodetectors. [ABSTRACT FROM AUTHOR]

β-Ga2O3 is an emerging ultra-wide bandgap semiconductor with wide-ranging applications from civil to military realms. Due to the varied surface states and upward band-bending of β-Ga2O3 with most metals, most of the conventional metal contacts turn out to be Schottky in nature, leading to a paucity of suitable Ohmic contacts to Ga2O3. Transparent conducting oxides (TCOs) offer the flexibility of conduction along with optical transparency, useful especially for optoelectronic devices. Herein, we report on the use of indium-zinc oxide (IZO), a TCO, as a suitable, unconventional contact to β-Ga2O3. The devices show a unique conversion from Schottky to Ohmic by annealing at an optimized temperature of 650 °C, while changing back to Schottky at higher temperatures. At 650 °C, the interface chemistry as studied by x-ray photoelectron spectroscopy changes drastically with band-bending of β-Ga2O3 shifting from upward to downward at the interface leading to a type II band alignment, responsible for the Schottky-to-Ohmic conversion. The results provide evidence of using IZO layer as an alternate contact material to β-Ga2O3 whose behavior as Ohmic or Schottky contact may be tuned by simply varying the annealing temperature and inducing interfacial changes at the semiconductor–electrode interface, while maintaining excellent device resilience. The proposed conducting oxide layer provides an effective strategy toward control and tunability in nature of contacts toward gallium oxide and its applications for high temperature resilience solar-blind photodetectors. [ABSTRACT FROM AUTHOR]

In this paper, CoMn based nanowires were in-situ grown on foam nickel by hydrothermal method combined with calcination treatment, and a monolithic methane oxidation catalyst was obtained. The effects of hydrothermal temperature and calcination temperature on the crystal structure, micro morphology and catalytic performance of the catalysts were systematically studied. The results indicated that when the hydrothermal temperature was 160 °C and the calcination temperature was 350 °C, Mn doped Co 3 O 4 nanowires with uniform morphology can be obtained, accompanied by the appearance of CoMn 2 O 4. The introduction of Mn ions caused lattice distortion of Co 3 O 4 , achieving the regulation of adsorbed oxygen and lattice oxygen. The monolithic MnCoO/NF–H-160 °C catalyst showed the best catalytic activity (T 90 = 414 °C) for lean methane catalytic oxidation, which even surpassed the noble metal based catalyst. Its excellent catalytic activity was due to the fact that the catalyst can expose more active sites, rich active oxygen and good mass transfer characteristics. This study provides a new approach for designing efficient monolithic catalysts and has significant potential for application and development in the field of organic waste gas treatment. [ABSTRACT FROM AUTHOR]

Co-precipitation method was applied to prepare five Cu-containing spinels CuB 2 O 4 with different B-sites (CuCo 2 O 4 , CuAl 2 O 4 , CuMn 2 O 4 , CuLa 2 O 4 , CuCr 2 O 4) and the physicochemical properties of the spinels were characterized comprehensively. The Cu-containing spinels were then washcoated on Cu foams to fabricate monolithic catalysts and the catalytic performance of the catalysts under different reaction conditions was investigated in a methanol steam reforming microreactor. The effects of B-site on the structure-activity relationship and sustained release catalysis were discussed in detail. Results showed that the CuCo 2 O 4 spinel with small particles, excellent reducibility, low acidity, large specific surface area and superior surface chemical state led to the best performance of the monolithic catalyst loaded with CuCo 2 O 4. The B-site resulted in completely different characteristics of spinels, leading to diverse sustained release properties during the catalysis. Owing to the sustained release behavior, the catalytic stability of the Cu-containing spinel was significantly improved compared with the conventional Cu-based catalyst. • Cu-containing spinels with different B-sites were used for methanol steam reforming. • CuCo 2 O 4 spinel exhibited the best performance due to its excellent characteristics. • The effects of B-site on the structure-activity relationship were discussed. • The process of the sustained release catalysis was proposed. [ABSTRACT FROM AUTHOR]

The Photoelectron-Related Image and Nano-Spectroscopy (PRINS) endstation located at the Taiwan Photon Source beamline 27A2 houses a photoelectron momentum microscope capable of performing direct-space imaging, momentum-space imaging and photoemission spectroscopy with position sensitivity. Here, the performance of this microscope is demonstrated using two in-house photon sources - an Hg lamp and He(I) radiation - on a standard checkerboard-patterned specimen and an Au(111) single crystal, respectively. By analyzing the intensity profile of the edge of the Au patterns, the Rashbasplitting of the Au(111) Shockley surface state at 300 K, and the photoelectron intensity across the Fermi edge at 80 K, the spatial, momentum and energy resolution were estimated to be 50 nm, 0.0172 Å-1 and 26 meV, respectively. Additionally, it is shown that the band structures acquired in either constant energy contour mode or momentum-resolved photoemission spectroscopy mode were in close agreement. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs), as emerging long afterglow luminescent material, have attracted the attention of researchers and become one of the hot topics in long afterglow materials. In recent years, researchers have obtained a series of CDs‐based long afterglow materials with different properties utilizing matrix‐assisted and self‐protective methods. To meet diverse application needs, the development of multicolor CDs‐based long afterglow materials is a focus and challenge in this field. Most of the previously reported CDs‐based long afterglow materials generally emit blue or green afterglow. Recently, some multicolor systems have been discovered, and the emission range can extend from ultraviolet to near‐infrared. However, there is a lack of systematic and in‐depth analysis regarding the preparation strategy and luminescence mechanism of multicolor afterglow from CDs‐based long afterglow materials. Based on this, this review summarizes the preparation strategies of multicolor afterglow from raw materials and reaction parameters. Then, the luminescence mechanisms of multicolor afterglow are analyzed from seven factors, including carbonization degree, surface state, aggregation degree, temperature dependence, excitation dependence, multi‐emission center, and energy transfer. Moreover, the applications of multicolor afterglow from CDs‐based long afterglow materials are introduced. Finally, the problems and challenges in this field are discussed, and the future development directions are analyzed. [ABSTRACT FROM AUTHOR]

We calculate, within the density-functional theory, the atomic and electronic structure of the clean Pt(111) and Au(111) surfaces and the nML-Au/Pt(111) systems with n varying from one to three. The effect of the spin–orbital interaction was taken into account. Several new electronic states with strong localization in the surface region were found and discussed in the case of clean surfaces. The Au adlayers introduce numerous quantum well states in the energy regions corresponding to the projected bulk band continuum of Au(111). Moreover, the presence of states resembling the true Au(111) surface states can be detected at n = 2 and 3. The Au/Pd interface states are found as well. In nML-Au/Pt(111), the calculated work function presents a small variation with a variation of the number of the Au atomic layer. Nevertheless, the effect is significantly smaller in comparison to the s-p metals. [ABSTRACT FROM AUTHOR]

The nonlinear optical properties of carbon dots have been in the spotlight in recent years. In light of the complexity and diversity of factors affecting the nonlinear optical properties of carbon dots, how to reveal the origin and physical mechanism of the nonlinear optical properties of carbon dots accurately has become a problem. In this work, a template-free method was designed to prepare carbon dots via solid-phase reaction with phloroglucinol as a single carbon source and sodium bisulfate as the catalyst. This method is simple, green, safe, and easy to be prepared on a large scale. Three carbon dots with different luminous colors were obtained by simply adjusting the reaction temperature. The rise of reaction temperature affects the surface functional groups, and then hinders the luminescence of surface states, leading to the change of luminescence properties. The nonlinear optical properties of carbon dots were analyzed by the Z-scan technique. Surprisingly, all carbon dots have nonlinear optical responses, but there are differences in performance. Results prove the increase in sp2 domains may contribute to the significant improvement of the nonlinear optical properties of carbon dots, indicating a direction to improve the nonlinear optical properties of carbon dots. [ABSTRACT FROM AUTHOR]

Currently, many researchers are interested in investigating the electric field in the fair-weather electric environment, along with its diurnal and seasonal variations across all regions of the world. However, a similar study in the southern part of Siberia has not yet been carried out. In this regard, this study aims to estimate the mean values of the electric field and their variations in the mountain and steppe landscapes using the measurement data from the Khakass–Tyva expedition in 2022. The maximum values of positive ion density were noted at the site in the Iyussko-Shirinsky steppe between Belyo and Tus salt lakes in the Khakass-Minusinsk Basin. The maximum values of negative ion density were observed at the site in the Shol tract in the center part of the Tyva depression. The potential gradient tends to increase with altitude and reaches a maximum in the highlands. The maximum values of the potential gradient were noted in the highlands plateau near the Mongun-Taiga Mountain Massif and Khindiktig-Khol Lake. The diurnal cycles of potential gradient at different observation sites were divided into two groups: (1) a diurnal cycle in the form of a double wave; and (2) a daily cycle with a more complex course due to the strong influence of local factors. [ABSTRACT FROM AUTHOR]

The presence of surface trap states (STSs) is one of the key factors to affect the electronic and optical properties of quantum dots (QDs), however, the exact mechanism of how STSs influence QDs remains unclear. Herein, we demonstrated the impact of STSs on electron transfer in CdSe QDs and triplet-triplet energy transfer (TTET) from CdSe to surface acceptor using femtosecond transient absorption spectroscopy. Three types of colloidal CdSe QDs, each containing various degrees of STSs as evidenced by photoluminescence and X-ray photoelectron spectroscopy, were employed. Time-resolved emission and transient absorption spectra revealed that STSs can suppress band-edge emission effectively, resulting in a remarkable decrease in the lifetime of photoelectrons in QDs from 17.1 ns to 4.9 ns. Moreover, the investigation of TTET process revealed that STSs can suppress the generation of triplet exciton and effectively inhibit band-edge emission, leading to a significant decrease in TTET from CdSe QDs to the surface acceptor. This work presented evidence for STSs influence in shaping the optoelectronic properties of QDs, making it a valuable point of reference for understanding and manipulating STSs in diverse QDs-based optoelectronic applications involving electron and energy transfer. [ABSTRACT FROM AUTHOR]

Due to recent advances in the development of land data assimilation systems (LDAS) and the availability of high-quality, satellite-based surface soil moisture (SSM) retrieval products, we now have unambiguous evidence that the assimilation of SSM retrievals, or their proxy, can improve the precision (i.e., correlation versus truth) of surface state estimates provided by a land surface model (LSM). However, this clarity does not yet extend to the estimation of LSM surface water fluxes that are key to hydrologic and numerical weather forecasting applications. Here, we hypothesize that a key obstacle to extrapolating realized improvements in water state precision into comparable improvements in water flux accuracy (i.e., mean absolute error) is the presence of water state–water flux coupling strength biases existing in LSMs. To test this hypothesis, we conduct a series of synthetic fraternal twin data assimilation experiments where realistic levels of state–flux coupling strength bias—involving both evapotranspiration and runoff—are systematically introduced into an assimilation LSM. Results show that the accuracy of the resulting water flux analysis is sharply reduced by the presence of such bias, even in cases where the precision of soil moisture state estimates (e.g., SSM) is improved. The rescaling of SSM observations prior to their assimilation (i.e., the most common approach for addressing systematic differences between LSMs and assimilated observations) is not always a robust strategy for addressing these errors and can, in certain circumstances, degrade water flux accuracy. Overall, results underscore the critical need to assess, and correct for, LSM water state–water flux coupling strength biases during the operation of an LDAS. Significance Statement: Land data assimilation is the process by which land surface model estimates of water states (e.g., soil moisture) and water fluxes (e.g., runoff and evapotranspiration) are improved via the incorporation of observations. Over the past decade, substantial improvements have been made in the precision of land surface model states via the assimilation of satellite-based soil moisture information. However, to date, these improvements have not yet been extended into water flux estimates like runoff and evapotranspiration. This is a critical shortcoming since advances in important weather and hydrologic forecasting applications are dependent on the improved estimation of such fluxes. We demonstrate that this shortcoming is linked to the inability of existing land surface models to accurately describe the impact of variations in water states on water fluxes and propose strategies for overcoming this issue in future land data assimilation systems. [ABSTRACT FROM AUTHOR]

This study investigates the performance of the latter NCEP Unified Forecast System (UFS) Coupled Model prototype simulations (P5–P8) during boreal summer 2011–17 in regard to coupled land–atmosphere processes and their effect on model bias. Major land physics updates were implemented during the course of model development. Namely, the Noah land surface model was replaced with Noah-MP and the global vegetation dataset was updated starting with P7. These changes occurred along with many other UFS improvements. This study investigates UFS's ability to simulate observed surface conditions in 35-day predictions based on the fidelity of model land surface processes. Several land surface states and fluxes are evaluated against flux tower observations across the globe, and segmented coupling processes are also diagnosed using process-based multivariate metrics. Near-surface meteorological variables generally improve, especially surface air temperature, and the land–atmosphere coupling metrics better represent the observed covariance between surface soil moisture and surface fluxes of moisture and radiation. Moreover, this study finds that temperature biases over the contiguous United States are connected to the model's ability to simulate the different balances of coupled processes between water-limited and energy-limited regions. Sensitivity to land initial conditions is also implicated as a source of forecast error. Above all, this study presents a blueprint for the validation of coupled land–atmosphere behavior in forecast models, which is a crucial model development task to assure forecast fidelity from day one through subseasonal time scales. [ABSTRACT FROM AUTHOR]

We perform large eddy simulations of flow past a circular cylinder for the Reynolds number (Re) range, 2 × 10 3 ≤ R e ≤ 4 × 10 5 , spanning subcritical, critical, and supercritical regimes. We investigate the spanwise coherence of the flow in the critical and supercritical regimes using complex networks. In these regimes, the separated flow reattaches to the surface in a turbulent state due to the turbulence generated by the shear layer instability. In the early critical regime, the turbulent reattachment does not occur simultaneously at all span locations. It occurs incoherently along the span in clusters. We treat strong surface pressure fluctuations due to the shear layer instability as extreme events and construct time-varying spatial proximity networks where links are based on synchronization between events. This analysis unravels the underlying complex spatiotemporal dynamics by enabling the estimation of characteristics of clusters of turbulent reattachment via the concept of connected components. In the critical regime, the number and size of the clusters increase with the increase in Re. At higher Re in the supercritical regime, they coalesce to form bigger clusters, resulting in increase in spanwise coherence of turbulent reattachment. We find that the size and number of clusters govern the variation of the time-averaged coefficient of drag ( C ¯ D ) in the critical and supercritical regimes. C ¯ D exhibits power-law distribution with the largest cluster size ( C ¯ D ∝ S ¯ C L − 2 5 ) and the most probable cluster size [ C ¯ D ∝ E (S C) − 2 5 ]. [ABSTRACT FROM AUTHOR]

In this work, the main electronic parameters of the performed Al-(CdxZn1-xO)-pSi Metal/Interface-layer/Semiconductor (MIS) type Schottky Diodes (SDs) were investigated by utilizing IV characteristics at 300 K. The (CdxZn1-xO) interfacial layer was grown on the pSi wafer by utilizing the sol-gel technique. Ideality-factor(n), potential barrier ФBo, Rs, shunt resistance (Rsh), and rectification rate (RR) (Iforward/Ireverse) values were calculated based on thermionic emission (TE) theory and Cheung function between -4.5V and 4.5V. There parameters also varied for the samples with different doping ratios. Energy-dependent surface state profiles of them were also extracted from the forward bias IV data, and their magnitude was found on the order of 1012eV-1.cm-2 which is very appropriate for the MIS type SD. The values of n, barrier height (BH), ФBo, and RR changed from 4.347, 0.582 eV, 5.74x10³ to 5.293, 0.607 eV, 2.83x106. These results show that electronic parameters of these SDs are a strong function of voltage, calculation method, and the doping rate of the Cadminium (Cd) interfacial layer. The best ratio for Cd: ZnO was determined to be 30%; therefore, this interfacial layer may be used instead of traditional insulator layers to enhance the quality of Metal/Semiconductor (MS) type SDs. [ABSTRACT FROM AUTHOR]

Analyzing the land surface states and their interlinkages with the atmosphere, improves the land-atmosphere interactions primarily. In this study, the initial state of the soil is generated using NASA's Land Information System (LIS). The ARW-WRF model (WRF), a widely employed mesoscale model is utilized to simulate the evolution of two Deep Depressions and two Monsoon Depressions, and their associated landfall in the coast adjoining the Head Bay of Bengal, and these simulations are called the "control run". Furthermore, the NASA Unified WRF (NUWRF) modeling system, that utilizes the initial equilibrium soil state, is also employed to simulate the aforementioned four depression systems, which are known as the "experimental run". While the accumulated precipitation values of both simulations are validated with the 3-hour accumulated precipitation data extracted from Indian Meteorological Department (IMD) daily accumulated precipitation data, the values of the top layer soil moisture of both simulations are compared with Indian Monsoon Data Assimilation and Analysis (IMDAA), Global Land Evaporation Amsterdam Model (GLEAM), and ESA's Climate Change Initiative soil moisture datasets (ESA-CCI). Both the ARW-WRF and NUWRF model simulations are analysed to investigate differences, if any, between the two model outputs and hence the effect of the improved soil state on the atmospheric variables. The results of the validation of top layer soil moisture (SM) with GLEAM, IMDAA and ESA-CCI datasets, clearly indicate that while the SM values of WRF run abruptly drops over the first two days, the abrupt drop in SM is not observed in the NUWRF run. Furthermore, none of the three SM datasets, show any abrupt drop in SM values, rather they show an increase in the SM values with time and then mostly little change of SM with time. The results also indicate that the WRF model typically shows higher values of the top layer SM as compared to NUWRF. Furthermore, at the time of the system's landfall, the output of both NUWRF and WRF models are compared for all four depressions. The variations in heat fluxes, surface air temperature, and planetary boundary layer height for the four systems are consistent with the differences shown in soil moisture for both WRF and NUWRF model simulations. Contiguous Rain Area (CRA) Verification method is utilized for verifying the gridded quantitative precipitation results with IMD's daily accumulated precipitation; which yielded mixed results. [ABSTRACT FROM AUTHOR]

BACKGROUND: The synthesis of sodium hypochlorite solutions by electrolysis of low‐concentration and isotonic NaCl solutions using the most available dimensionally stable anodes from platinized titanium is promising from the point of view of the economics of the process. However, such synthesis is seriously complicated by the formation of toxic sodium chlorate impurity. RESULTS: It is shown that in low‐concentration NaCl solutions under anodic polarization, the platinum surface rapidly passes into an oxidized passive state with a NaClO current efficiency (CE) of less than 30% and CE of NaClO3 of more than 20%. Carrying out short‐term electrolysis on the reduced surface of platinum makes it possible to increase the CE of NaClO to almost 90% in the absence of chlorate accumulation. Carrying out electrolysis in the mode of periodic change of electrode polarity (current reverse) allows solving the problem of anode passivation and significantly increasing the purity of the resulting sodium hypochlorite solutions. CONCLUSION: Electrolysis of an isotonic 0.15 mol L−1 NaCl solution in the current reverse mode allows increasing CE(NaClO) from 21% to 40% and significantly decreasing CE(NaClO3) from 21% to 4%. Based on the results obtained, a membraneless electrolyzer can be constructed to produce disinfectant solutions 'on the spot' using a commercially available pharmaceutical isotonic solution of NaCl. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Additive manufacturing is a new manufacturing technique that integrates laser, digitization, materials and other disciplines. It has the advantages of dimensionality reduction manufacturing, complex forming, and high material utilization. It is one of the most promising techniques in the field of material processing. Metal additive manufacturing technique has been widely studied and applied in the aviation field. The research on the additive manufacturing of aviation metal materials by domestic and foreign scholars continues to deepen. AECC Additive Manufacturing Technology Innovation Center has carried out a quantity of research and obtained some data from the four factors of metal additive manufacturing: microstructure, defects, surface and configuration. Some phenomena and laws have been found, including the characteristics and influencing factors of microstructure continuous growth; influence of the structure on mechanical properties; the characteristics and causes of common defects (pores, cracks, incomplete fusion) in additive manufactured typical materials and their influence mechanism on mechanical properties, especially fatigue properties; the relation between surface roughness and forming angles, and the influence of surface states on fatigue properties; factors influencing configuration of metal additive manufacturing. Finally, the problems existing in the development of metal additive manufacturing are summarized, and the suggestions for future research and development are put forward. [ABSTRACT FROM AUTHOR]

The ability to harness charges and spins for control of organic excitonic states is critical in developing high‐performance organic luminophores and optoelectronic devices. Here we report a facile strategy to efficiently manipulate the electronic energy states of various organic phosphors by coupling them with inorganic lanthanide nanocrystals. We show that the metallic atoms exposed on the nanocrystal surface can introduce strong coupling effects to 9‐(4‐ethoxy‐6‐phenyl‐1,3,5‐triazin‐2‐yl)‐9H‐carbazole (OCzT) and some organic chromophores with carbazole functional groups when the organics are approaching the nanocrystals. This unconventional organic–inorganic hybridization enables a nearly 100 % conversion of the singlet excitation to fast charge transfer luminescence that does not exist in pristine organics, which broadens the utility of organic phosphors in hybrid systems. [ABSTRACT FROM AUTHOR]

The recent progress in CuMnAs and Mn3X (X = Sn, Ge, Pt) shows that antiferromagnets (AFMs) provide a promising platform for advanced spintronics device innovations. Most recently, a switchable Fermi‐arc is discovered by the ARPES technique in antiferromagnet NdBi, but the knowledge about electron‐transport property and the manipulability of the magnetic structure in NdBi is still vacant to date. In this study, SdH oscillations are successfully verified from the Dirac surface states (SSs) with 2‐dimensionality and nonzero Berry phase. Particularly, it is observed that the spin‐flop transition only appears when the external magnetical field is applied along [001] direction, and features obvious hysteresis for the first time in NdBi, which provides a powerful handle for adjusting the spin texture in NdBi. Crucially, the DFT shows the Dirac cone and the Fermi arc strongly depend on the high‐order magnetic structure of NdBi and further reveals the orbital magnetic moment of Nd plays a crucial role in fostering the peculiar SSs, leading to unveil the mystery of the band‐splitting effect and to manipulate the electronic transport, high‐effectively, in the thin film works in NdBi. It is believed that this study provides important guidance for the development of new antiferromagnet‐based spintronics devices based on cutting‐edge rare‐earth monopnictides. [ABSTRACT FROM AUTHOR]

Given the rarity of metallic systems that exhibit ferroelectric-like transitions, it is apparently challenging to find a system that simultaneously possesses superconductivity and ferroelectric-like structural instability. Here, we report the observation of superconductivity at 2.4 K in a layered semimetal SrAuBi characterized by strong spin–orbit coupling (SOC) and ferroelectric-like lattice distortion. Single crystals of SrAuBi have been successfully synthesized and found to show a polar-nonpolar structure transition at 214 K, which is associated with the buckling of Au-Bi honeycomb lattice. On the basis of the band calculations considering SOC, we found significant Rashba-type spin splitting and symmetry-protected multiple Dirac points near the Fermi level. We believe that this discovery opens up new possibilities of pursuing exotic superconducting states associated with the semimetallic band structure without space inversion symmetry and the topological surface state with the strong SOC. [ABSTRACT FROM AUTHOR]

SmB6, a topological Kondo insulator, possesses topologically protected surface states, in which carrier mobility is supposed to be high but is significantly varied in orders of magnitude dependent upon characterization methods. Herein, we performed magnetoresistance measurements on a Hall-bar device constructed on a highly uniform SmB6 nanoribbon with (001) surface grown by chemical vapor deposition. Unusual non-linear Hall resistance was observed at low temperature and explained with a two-carrier model. The two types of carriers were attributed to two types of Fermi pockets on the Brillouin zone of the SmB6 (001) surface. The Fermi pocket on Γ point provided high hole mobility up to 1.4 × 10 3 cm2/V s but low hole density at a temperature of 2.2 K. On the other hand, the Fermi pockets on X points supplied low electron mobility down to 1.8 cm2/V s but high electron density. The identification of the two types of pockets laid the foundation for the understanding of the transport via the topological surface states of the SmB6 (001) surface. [ABSTRACT FROM AUTHOR]

The unique features of spinless time-reversal symmetry and tunable ℤ 2 gauge fields in artificial systems facilitate the emergence of topological properties in the landscape, such as the recently explored Möbius-twisted phase and real second-order nodal-loop semimetals. However, these properties have predominantly been proposed only in theoretical frameworks. In this study, we present a cunningly designed blueprint for realizing an acoustic real second-order nodal-loop semimetal through the incorporation of projective translation symmetry into a three-dimensional stacked acoustic graphitic lattice. Additionally, we introduce non-Hermitian modulation to the topologically protected propagation of degenerate drumhead surface and hinge states, which depend on the specific on-site gain and loss textures. It should be emphasized that this demonstration can be extended to other classical wave systems, thereby potentially opening up opportunities for the design of functional topological devices. [ABSTRACT FROM AUTHOR]

Lead chalcogenide nanoplatelets (NPLs) have emerged as a promising material for devices operating in the near IR and IR spectrum region. Here, we first apply the cation exchange method to PbSe/PbS core/shell NPL synthesis. The shell growth enhances NPL colloidal and environmental stability, and passivates surface trap states, preserving the main core physical properties. To prove the great potential for optoelectrical applications, we fabricate a photoconductor using PbSe/PbS NPLs. The device demonstrates enhanced conductivity and responsivity with fast rise and fall times, resulting in a 13 kHz bandwidth. The carrier transport was investigated with the field effect transistor method, showing p-type conductivity with charge mobility of 1.26 × 10−2 cm2·V−1·s−1. [ABSTRACT FROM AUTHOR]