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IntroductionBiological nitrogen fixation (BNF) plays a crucial role in nitrogen utilization in agroecosystems. Functional characteristics of plants (grasses vs. legumes) affect BNF. However, little is still known about how ecological zones and cropping patterns affect legume nitrogen fixation. This study’s objective was to assess the effects of different cropping systems on aboveground dry matter, interspecific relationships, nodulation characteristics, root conformation, soil physicochemistry, BNF, and nitrogen transfer in three ecological zones and determine the main factors affecting nitrogen derived from the atmosphere (Ndfa) and nitrogen transferred (Ntransfer).MethodsThe 15N labeling method was applied. Oats (Avena sativa L.), forage peas (Pisum sativum L.), common vetch (Vicia sativa L.), and fava beans (Vicia faba L.) were grown in monocultures and mixtures (YS: oats and forage peas; YJ: oats and common vetch; YC: oats and fava beans) in three ecological regions (HZ: Huangshui Valley; GN: Sanjiangyuan District; MY: Qilian Mountains Basin) in a split-plot design.ResultsThe results showed that mixing significantly promoted legume nodulation, optimized the configuration of the root system, increased aboveground dry matter, and enhanced nitrogen fixation in different ecological regions. The percentage of nitrogen derived from the atmosphere (%Ndfa) and percentage of nitrogen transferred (%Ntransfer) of legumes grown with different legume types and in different ecological zones were significantly different, but mixed cropping significantly increased the %Ndfa of the legumes. Factors affecting Ndfa included the cropping pattern, the ecological zone (R), the root nodule number, pH, ammonium-nitrogen, nitrate-nitrogen, microbial nitrogen mass (MBN), plant nitrogen content (N%), and aboveground dry biomass. Factors affecting Ntransfer included R, temperature, altitude, root surface area, nitrogen-fixing enzyme activity, organic matter, total soil nitrogen, MBN, and N%.DiscussionWe concluded that mixed cropping is beneficial for BNF and that mixed cropping of legumes is a sustainable and effective forage management practice on the Tibetan Plateau.

Abstract Spintronic device is the fundamental platform for spin-related academic and practical studies. However, conventional techniques with energetic deposition or boorish transfer of ferromagnetic metal inevitably introduce uncontrollable damage and undesired contamination in various spin-transport-channel materials, leading to partially attenuated and widely distributed spintronic device performances. These issues will eventually confuse the conclusions of academic studies and limit the practical applications of spintronics. Here we propose a polymer-assistant strain-restricted transfer technique that allows perfectly transferring the pre-patterned ferromagnetic electrodes onto channel materials without any damage and change on the properties of magnetism, interface, and channel. This technique is found productive for pursuing superior-quality spintronic devices with high controllability and reproducibility. It can also apply to various-kind (organic, inorganic, organic-inorganic hybrid, or carbon-based) and diverse-morphology (smooth, rough, even discontinuous) channel materials. This technique can be very useful for reliable device construction and will facilitate the technological transition of spintronic study.

IntroductionModern agriculture emphasizes the design of cropping systems using ecological function and production services to achieve sustainability. The functional characteristics of plants (grasses vs. legumes) affect changes in soil microbial communities that drive agroecosystem services. Information on the relationship between legume-grass mixtures and soil microorganisms in different ecological zones guides decision-making toward eco-friendly and sustainable forage production. However, it is still poorly understood how cropping patterns affect soil microbial diversity in alpine grasslands and whether this effect varies with altitude.MethodsTo fill this gap in knowledge, we conducted a field study to investigate the effects of growing oats (Avena sativa L.), forage peas (Pisum sativum L.), common cornflower (Vicia sativa L.), and fava beans (Vicia faba L.) in monocultures and mixtures on the soil microbial communities in three ecological zones of the high alpine zone.ResultsWe found that the fungal and bacterial community structure differed among the cropping patterns, particularly the community structure of the legume mixed cropping pattern was very different from that of monocropped oats. In all ecological zones, mixed cropping significantly (p < 0.05) increased the α-diversity of the soil bacteria and fungi compared to oat monoculture. The α-diversity of the soil bacteria tended to increase with increasing elevation (MY [2,513 m] < HZ [2,661 m] < GN [3,203 m]), while the opposite was true for fungi (except for the Chao1 index in HZ, which was the lowest). Mixed cropping increased the abundance of soil fungi and bacteria across ecological zones, particularly the relative abundances of Nitrospira, Nitrososphaera, Phytophthora, and Acari. Factors affecting the bacterial community structure included the cropping pattern, the ecological zone, water content, nitrate-nitrogen, nitrate reductase, and soil capacity, whereas factors affecting fungal community structure included the cropping pattern, the ecological zone, water content, pH, microbial biomass nitrogen, and catalase.DiscussionOur study highlights the variation in soil microbial communities among different in alpine ecological regions and their resilience to cropping systems. Our results also underscore that mixed legume planting is a sustainable and effective forage management practice for the Tibetan Plateau.

Abstract The spin degree of freedom is an important and intrinsic parameter in boosting carrier dynamics and surface reaction kinetics of photocatalysis. Here we show that chiral structure in ZnO can induce spin selectivity effect to promote photocatalytic performance. The ZnO crystals synthesized using chiral methionine molecules as symmetry-breaking agents show hierarchical chirality. Magnetic circular dichroism spectroscopic and magnetic conductive-probe atomic force microscopic measurements demonstrate that chiral structure acts as spin filters and induces spin polarization in photoinduced carriers. The polarized carriers not only possess the prolonged carrier lifetime, but also increase the triplet species instead of singlet byproducts during reaction. Accordingly, the left- and right-hand chiral ZnO exhibit 2.0- and 1.9-times higher activity in photocatalytic O2 production and 2.5- and 2.0-times higher activities in contaminant photodegradation, respectively, compared with achiral ZnO. This work provides a feasible strategy to manipulate the spin properties in metal oxides for electron spin-related redox catalysis.

Nitrogen (N) addition is a simple and effective field management approach to enhancing plant productivity. Nonetheless, the regulatory mechanisms governing nitrogen concentrations and their effect on soil enzyme activity, nutrient levels, and seed yield in the Festuca kirilowii seed field have yet to be elucidated. Therefore, this study sought to investigate the effect of N fertilizer application on soil enzyme activities, soil nutrients, and seed yield of F. kirilowii Steud cv. Huanhu, the only domesticated variety in the Festuca genus of the Poaceae family, was investigated based on two-year field experiments in the Qinghai–Tibet Plateau (QTP). Results showed that N input significantly affected soil nutrients (potential of hydrogen, total nitrogen, organic matter, and total phosphorus). In addition, soil enzyme activities (urease, catalase, sucrase, and nitrate reductase) significantly increased in response to varying N concentrations, inducing changes in soil nutrient contents. Introducing N improved both seed yield and yield components (number of tillers and number of fertile tillers). These findings suggest that the introduction of different concentrations of N fertilizers can stimulate soil enzyme activity, thus hastening nutrient conversion and increasing seed yield. The exhaustive evaluation of the membership function showed that the optimal N fertilizer treatment was N4 (75 kg·hm−2) for both 2022 and 2023. This finding provides a practical recommendation for improving the seed production of F. kirilowii in QTP.

IntroductionInformation on the relationship between soil quality and forage yield of legume-grass mixtures in different ecological regions can guide decision-making to achieve eco-friendly and sustainable pasture production. This study’s objective was to assess the effects of different cropping systems on soil physical properties, nitrogen fractions, enzyme activities, and forage yield and determine suitable legume-grass mixtures for different ecoregions.MethodsOats (Avena sativa L.), forage peas (Pisum sativum L.), common vetch (Vicia sativa L.), and fava beans (Vicia faba L.) were grown in monocultures and mixtures (YS: oats and forage peas; YJ: oats and common vetch; YC: oats and fava beans) in three ecological regions (HZ: Huangshui Valley; GN: Sanjiangyuan District; MY: Qilian Mountains Basin) in a split-plot design.ResultsThe results showed that the forage yield decreased with increasing altitude, with an order of GN (3203 m a.s.l.; YH 8.89 t·ha-1) < HZ (2661 m; YH 9.38 t·ha-1) < MY (2513m; YH 9.78 t·ha-1). Meanwhile, the forage yield was higher for mixed crops than for single crops in all ecological regions. In the 0-10 cm soil layer, the contents of total nitrogen (TN), microbial biomass nitrogen (MBN), soil organic matter (SOM), soluble organic nitrogen (SON), urease (UE), nitrate reductase (NR), sucrase (SC), and bacterial community alpha diversity, as well as relative abundance of dominant bacteria, were higher for mixed crops than for oats unicast. In addition, soil physical properties, nitrogen fractions, and enzyme activities varied in a wider range in the 0-10 cm soil layer than in the 10-20 cm layer, with larger values in the surface layer than in the subsurface layer. MBN, SON, UE, SC and catalase (CAT) were significantly and positively correlated with forage yield (P < 0.05). Ammonium nitrogen (ANN), nitrate nitrogen (NN), SOM and cropping systems (R) were significantly and positively correlated with Shannon and bacterial community (P < 0.05). The highest yields in the three ecological regions were 13.00 t·ha-1 for YS in MY, 10.59 t·ha-1 for YC in GN, and 10.63 t·ha-1 for YS in HZ.DiscussionWe recommend planting oats and forage peas in the Qilian Mountains Basin, oats and fava beans in the Sanjiangyuan District, and oats and forage peas in Huangshui valley. Our results provide new insights into eco-friendly, sustainable, and cost-effective forage production in the Qinghai Alpine Region in China.

Abscisic acid (ABA) is a phytohormone that plays an important role in plant growth and development. Meanwhile, ABA also plays a key role in the plant response to abiotic stressors such as drought and high salinity. The pyrabactin resistance 1-like (PYR/PYL) protein family of ABA receptors is involved in the initial step of ABA signal transduction. However, no systematic studies of the PYL family in “Avena sativa, a genus Avena in the grass family Poaceae,” have been conducted to date. Thus, in this study, we performed a genome-wide screening to identify PYL genes in oat and characterized their responses to drought stress. A total of 12 AsPYL genes distributed on nine chromosomes were identified. The phylogenetic analysis divided these AsPYLs into three subfamilies, based on structural and functional similarities. Gene and motif structure analysis of AsPYLs revealed that members of each subfamily share similar gene and motif structure. Segmental duplication appears to be the driving force for the expansion of PYLs, Furthermore, stress-responsive AsPYLs were detected through RNA-seq analysis. The qRT-PCR analysis of 10 AsPYL genes under drought, salt, and ABA stress revealed that AsPYL genes play an important role in stress response. These data provide a reference for further studies on the oat PYL gene family and its function.

Abstract The van der Waals (vdW) ferromagnet Fe3‐δGeTe2 has garnered significant research interest as a platform for skyrmionic spin configurations, that is, skyrmions and skyrmionic bubbles. However, despite extensive efforts, the origin of the Dzyaloshinskii–Moriya interaction (DMI) in Fe3‐δGeTe2 remains elusive, making it challenging to acquire these skyrmionic phases in a controlled manner. In this study, it is demonstrated that the Fe content in Fe3‐δGeTe2 has a profound effect on the crystal structure, DMI, and skyrmionic phase. For the first time, a marked increase in Fe atom displacement with decreasing Fe content is observed, transforming the original centrosymmetric crystal structure into a non‐centrosymmetric symmetry, leading to a considerable DMI. Additionally, by varying the Fe content and sample thickness, a controllable transition between Néel‐type skyrmions and Bloch‐type skyrmionic bubbles is achieved, governed by a delicate interplay between dipole–dipole interaction and the DMI. The findings offer novel insights into the variable skyrmionic phases in Fe3‐δGeTe2 and provide the impetus for developing vdW ferromagnet‐based spintronic devices.

The discovery of ferromagnetic two-dimensional (2D) materials provides reference value for the exploration of low-dimensional magnetism and new spintronic devices. The VSi2N4 monolayer is ferromagnetic with half-metallic characteristics, which is a new 2D material in the field of spintronics. Here, the electronic structure and magnetic anisotropy of two-dimensional VSi2X2N2 (X = P, As, Sb, Bi) Janus monolayers are studied systematically via first-principles calculations. The results show that VSi2P2N2, VSi2As2N2 and VSi2Bi2N2 are magnetic, but VSi2Sb2N2 is nonmagnetic. At X = P, As and Bi, VSi2X2N2 Janus monolayers are metallic and ferromagnetic. VSi2P2N2 and VSi2As2N2 show the in-plane magnetic anisotropy, while VSi2Bi2N2 shows the perpendicular magnetic anisotropy (PMA). As the tensile strain increases, the spin-down energy band of the VSi2P2N2 monolayer gradually moves up and the spin-up channel moves down. At ε = +12%, the spin-down band shifts above the Fermi level, showing the half-metallic characteristic with a band gap of 0.775 eV calculated using the Perdew–Burke–Ernzerhof (PBE) exchange–correlation function. The magnetic moment of VSi2Sb2N2 is induced at an electric field of −0.4 V/Å and +0.2 V/Å, where PMA appears. These data provide basic theoretical guidance for the development of low-dimensional spintronic devices.

Artificial enzymes with reprogrammed and augmented catalytic activity and substrate selectivity have emerged to tackle limitations of noble metals or transition metal oxides. Here, the authors report Au25 clusterzymes which are endowed with high catalytic activity and selectivity in a range of enzyme-mimicking reactions.

Spin-polarized current manipulation of magnetic skyrmions is energy consuming. Here, the authors achieve an electric-field manipulation of individual skyrmions in a nanostructured ferromagnetic/ferroelectrical heterostructure at room temperature via an inverse magneto-mechanical effect.

Photocatalyst activity depends significantly on the material’s electronic structures. Here, authors manipulate the electron spin polarization of TiO2 by tuning the concentration of Ti vacancies and show improved photocatalytic activities.

Induction of complex homochiral architectures by chiral transformation in a mixed enantiomer system has remained largely elusive. Here, the authors report a chirality dominance effect which induces homochiral suprastructures of calcium carbonate by a mixed, heterochiral nonracemic amino acid enantiomer system.

Winter rapeseed is susceptible to low temperature during winter in Northwest China, which could lead to a severe reduction of crop production. The freezing temperature could stress the whole plant, especially the leaf, and ultimately harm the survival rate of winter rapeseed. However, the molecular mechanism underlying freezing tolerance is still unclear in winter rapeseed. In this study, a comprehensive investigation of winter rapeseed freezing tolerance was conducted at the levels of transcript, protein, and physiology and biochemistry, using a pair of freezing-sensitive and freezing-resistant cultivars NQF24 and 17NTS57. There were 4,319 unique differentially expressed genes (DEGs) and 137 unique differentially abundant proteins (DAPs) between two cultivars identified in leaf under freezing stress. Function enrichment analysis showed that most of the enriched DEGs and DAPs were involved in plant hormone signal transduction, alpha-linolenic/linoleic acid metabolism, peroxisome, glutathione metabolism, fatty acid degradation, and secondary metabolite biosynthesis pathways. Based on our findings, it was speculated that freezing tolerance formation is caused by increased signal transduction, enhanced biosynthesis of protein, secondary metabolites, and plant hormones, elevated energy supply, greater reactive oxygen species scavenging, and lower lipid peroxidation as well as stronger cell stability in leaf under freezing stress. These results provide a comprehensive profile of leaf response under freezing stress, which have potential to be used as selection indicators of breeding programs to improve freezing tolerance in rapeseed.

Two winter rapeseed cultivars, "NS" (cold tolerant) and "NF" (cold sensitive), were used to reveal the morphological, physiological, and proteomic characteristics in leaves of plants after treatment at -4°C for 12 h(T1) and 24 h(T2), and at room temperature(T0), to understand the molecular mechanisms of cold tolerance. Antioxidant activity and osmotic adjustment ability were higher, and plasma membrane injury was less obvious, in NS than in NF under cold stress. We detected different abundant proteins (DAPs) related to cold tolerance in winter rapeseed through data-independent acquisition (DIA). Compared with NF, A total of 1,235 and 1,543 DAPs were identified in the NSs under T1 and T2, respectively. Compared with NF, 911 proteins were more abundant in NS only after cold treatment. Some of these proteins were related to ROS scavenging through four metabolic pathways: lysine degradation; phenylalanine, tyrosine, and tryptophan; flavonoid biosynthesis; and ubiquinone and other terpenoid-quinone biosynthesis. Analysis of these proteins in the four candidate pathways revealed that they were rapidly accumulated to quickly enhance ROS scavenging and improve the cold tolerance of NS. These proteins were noticeably more abundant during the early stage of cold stress, which was critical for avoiding ROS damage.

Winter turnip rape (Brassica rapa L.) is an important overwintering oil crop that is widely planted in northwestern China. It considered to be a good genetic resource for cold-tolerant research because its roots can survive harsh winter conditions. Here, we performed comparative transcriptomics analysis of the roots of two winter turnip rape varieties, Longyou7 (L7, strong cold tolerance) and Tianyou2 (T2, low cold tolerance), under normal condition (CK) and cold stress (CT) condition. A total of 8,366 differentially expressed genes (DEGs) were detected between the two L7 root groups (L7CK_VS_L7CT), and 8,106 DEGs were detected for T2CK_VS_T2CT. Among the DEGs, two ω-3 fatty acid desaturase (FAD3), two delta-9 acyl-lipid desaturase 2 (ADS2), one diacylglycerol kinase (DGK), and one 3-ketoacyl-CoA synthase 2 (KCS2) were differentially expressed in the two varieties and identified to be related to fatty acid synthesis. Four glutamine synthetase cytosolic isozymes (GLN), serine acetyltransferase 1 (SAT1), and serine acetyltransferase 3 (SAT3) were down-regulated under cold stress, while S-adenosylmethionine decarboxylase proenzyme 1 (AMD1) had an up-regulation tendency in response to cold stress in the two samples. Moreover, the delta-1-pyrroline-5-carboxylate synthase (P5CS), δ-ornithine aminotransferase (δ-OAT), alanine-glyoxylate transaminase (AGXT), branched-chain-amino-acid transaminase (ilvE), alpha-aminoadipic semialdehyde synthase (AASS), Tyrosine aminotransferase (TAT) and arginine decarboxylase related to amino acid metabolism were identified in two cultivars variously expressed under cold stress. The above DEGs related to amino acid metabolism were suspected to the reason for amino acids content change. The RNA-seq data were validated by real-time quantitative RT-PCR of 19 randomly selected genes. The findings of our study provide the gene expression profile between two varieties of winter turnip rape, which lay the foundation for a deeper understanding of the highly complex regulatory mechanisms in plants during cold treatment.

One-dimensional nanoribbons: A platform for probing exotic magnetoresistance Electrically-tunable electron-hole pockets could make antimonene nanoribbons a platform for probing unusual magnetoresistance effects. Some material changes their resistance when a magnetic field is applied—an effect known as magnetoresistance. This phenomenon is harnessed for a range of technological applications but the origin of the recently observed large, non-saturating magnetoresistance in certain materials is somewhat puzzling. Using first-principles calculations, Wenbo Mi and Yan Song from Tianjin University, along with Xiaocha Wang from Tianjin University of Technology, predict that one-dimensional antimonene nanoribbons with a zigzag asymmetric washboard structure could have electron-hole pockets, which are the key features necessary for observing a non-saturating magnetoresistance. As these pockets could be modulated using in-plane electric fields, these nanoribbons could be a tunable platform for probing this exotic phenomenon.

We experimentally demonstrate a novel and simple method for the excitation of a curved surface plasmon polariton on a silver nanofilm. We generated an Airy-like shaped beam in the Fourier plane by using a fifth-power phase mask imposed on a spatial light modulator to excite surface plasmon polariton on the silver nanofilm consisting of silver nanoparticles. The intensity distribution of the surface plasmon polariton trajectories was recorded by the leakage radiation microscope, which indicates that a plasmonic polynomial beam is produced on the silver nanofilm. This method provides relatively commercial and dynamic manipulation of a curved surface plasmon polariton on a noble metallic nanofilm.

The spin-dependent transport properties through chiral amino acids and their modulations by light and magnetic field are important for understanding the intrinsic magnetism and photomagnetic coupling of chiral molecules. Here, the spin-dependent electronic transport through chiral methionine (R,S-MET) molecules is studied by theoretical calculations through a magnetic tunnel junction (MTJ) model. R-MET molecule outputs fully spin polarized photocurrents with different spin channels, while S-MET is insensitive under polarized light, revealing the spin polarized photocurrent selectivity of chiral molecules. Photocurrent increases greatly in Fe4N/S-MET/Au MTJ, where S-MET shows unidirectional spin filtering effect. Fully spin polarized photocurrent appears in Fe4N/R,S-MET/Au MTJs, whose spin channel can be switched by adjusting magnetization directions. Particularly, chiral-induced spin selectivity effect appears in Fe4N/R,S-MET/Au MTJs under specific polarized light and magnetization direction. Understanding the spin-dependent electronic transport of chiral amino acids can provide a theoretical foundation for life science and bioelectronic devices. [ABSTRACT FROM AUTHOR]

Organic materials with mechanical flexibility, low cost, chemical engineering, and long spin lifetime attract considerable attention for building spintronic devices. Here, a C6H6/Co2MnSi(001) spinterface is investigated by first-principles calculations and spin-polarized scanning tunneling microscopy simulations. Several high symmetry adsorption sites are discussed, together with two possible surface terminations of Co2MnSi(001). An inversion of the spin polarization is induced near EF even in the case of an external electric field, indicating that C66 can act as a spin filter to exploit the spin injection efficiency in organic spintronic devices. Unlike previous studies on molecule/ferromagnet interfaces, this inversion is closely related to the electronic structure of the atoms in the subsurface layer of Co2MnSi according to the orbital symmetry analysis. Furthermore, the magnetic moment and magnetic anisotropic energy (MAE) in the outermost Co2MnSi layer are studied. Particularly, in the most stable configuration, the sign of MAE is inversed due to hybridization between C p and Co dz2 orbitals, which suggests that a greater modification on MAE can be achieved by the use of a highly chemically reactive organic molecule. These findings improve the study on the engineering of magnetic properties at molecule/ferromagnetic interfaces through a single π-conjugated organic molecule. [ABSTRACT FROM AUTHOR]

The electronic structure of C6H6/Fe3O4(001) interfaces has been investigated by the density functional theory. It is found that a weaker interaction exists between C6H6 and Fe3O4(001) in the adsorption models by comparing with the previous studies. The electronic states of C6H6 show a slight spin-splitting, which has the potential applications as a molecular spin filter. Meanwhile, a valence transition from Fe3+ to Fe2+ occurs in one model, which reduces the magnetic moment. The transition can be ascribed to the geometric distortion induced by C6H6 adsorption, which depicts the re-interaction process among Fe3O4(001) atoms. Furthermore, the high spatial spin polarization of C6H6/Fe3O4(001) appears with the increased density of states at EF. The calculated results offer a new mechanism to manipulate the interfacial electronic structure through C6H6 adsorption, which has the potential applications in organic spintronic devices. [ABSTRACT FROM AUTHOR]

The electronic and magnetic properties of La2/3Sr1/3MnO3(LSMO)/tetragonal BiFeO3(BFO) heterostructures with the xy-plane biaxial strain were investigated by first-principles calculations. As the xy-plane lattice constant is ranging from 3.619 to 3.921 Å, a large interfacial magnetoelectric coupling (IMEC) appears in the LaO/Fe-O2 and LaO/O2-Fe models. Particularly, the interfacial Mn in the LaO/O2-Fe model shows a large spin-down t2g orbital splitting at a strain from -2% to 6%, where the maximum splitting energy is 283 meV at 2%. Additionally, the LaO/O2-Fe model is half-metallic at a strain of 2%, 4%, and 6%. The results demonstrate that IMEC, orbital occupancy, and half-metallicity of LSMO/BFO heterostructures can be effectively engineered by the interfacial coupling and in-plane strain, which paves a way for designing the novel magnetoelectric devices. [ABSTRACT FROM AUTHOR]

We report the first-principles calculations on the electronic structure and simulation of the spin-polarized scan tunneling microscopy graphic of the small organic molecules (benzene, thiophene, and cyclopentadienyl)/Fe4N interfaces. It is found that the plane of benzene and thiophene keeps parallel to Fe4N surface, while that of cyclopentadienyl does not. For all the systems, the organic molecules bind strongly with Fe4N. Due to the hybridization between molecule pz orbitals and d orbitals of Fe, i.e., Zener interaction, all the three systems realize the spin-polarization inversion, whereas the spatial spin-polarization inversion distribution shows different intensities influenced by the competition between the spin polarization of C pz and Fe d states. [ABSTRACT FROM AUTHOR]

We investigated the structure, magnetic, and transport properties of ZnFe2O4 (ZFO) by both experimental and first-principles study. The epitaxial ZFO films prepared with various oxygen partial pressures show clear semiconducting behavior and room-temperature ferrimagnetism. A large magnetoresistance of -21.2% was observed at 75 K. The room-temperature ferrimagnetism is induced by the cation disordering. The calculated results indicate that under cation disordering, the ZFO with various oxygen vacancies is a half-metal semiconductor with both possible positive and negative signs of the spin polarization, while ZFO with no oxygen vacancies is an insulator and can be acted as the spin filter layer in spintronic devises. [ABSTRACT FROM AUTHOR]

Software defect prediction is an important way to find software defects and improve software quality. In recent years, with the rapid development of the software industry and the continuous improvement of data mining technology, a large amount of labeled software data is continuously generated to form a software data stream. However, traditional software defect prediction based on batch learning cannot fully adapt to this form of data flow, so a method of software defects prediction incremental model using ensemble learning (SDPIE) is proposed to learn and process real-time software data streams. In this process, the under-sampling method and selective learning method are used to solve the problem of software data imbalance and the increase of the incremental learning classifier scale. Through a comparison with two incremental learning algorithms and two batch learning algorithms, it is shown that the SDPIE algorithm can effectively control the size of the algorithm and the prediction performance is better than the other four comparison algorithms. [ABSTRACT FROM AUTHOR]

Electric field control on perpendicular magnetic anisotropy (PMA) is indispensable for spintronic devices. Herewith, in tetragonal Fe4N/BiFeO3 heterostructures with the FeAFeB/Fe-O2 interface, PMA in each Fe4N layer, not merely interfacial layers, is modulated by the electric field, which is attributed to the broken spin screening of the electric field in highly spin-polarized Fe4N. Moreover, the periodical dxy + dyz + dz2 and dxy + dx2 - y2 orbital-PMA oscillation enhances the interactions between adjacent FeAFeB and (FeB)2N atomic layers, which benefits the electric field modulation on PMA in the whole Fe4N atomic layers. The electric-field control on PMA in Fe4N/ BiFeO3 heterostructures is favored by the electric-field-lifted potential in Fe4N. [ABSTRACT FROM AUTHOR]

We analyze the electronic structure of interfaces between two-, four- and six-layer Gd(0001) and monolayer MoS2 by first-principles calculations. Strong chemical bonds shift the Fermi energy of MoS2 upwards into the conduction band. At the surface and interface the Gd f states shift to lower energy and new surface/ interface Gd d states appear at the Fermi energy, which are strongly hybridized with the Mo 4d states and thus lead to a high spin-polarization (ferromagnetically ordered Mo magnetic moments of 0.15 μB). Gd therefore is an interesting candidate for spin injection into monolayer MoS2. [ABSTRACT FROM AUTHOR]

The reactions of electron-rich organosilicon compounds 1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (1), 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (2), and 1,1′-bis(trimethylsilyl)-1,1′-dihydro-4,4′-bipyridine (12) with B-amino and B-aryl dihaloboranes afforded a series of novel B=N-bond-containing compounds 3–11 and 13. The B=N rotational barriers of 7 (>71.56 kJ/mol), 10 (58.79 kJ/mol), and 13 (58.65 kJ/mol) were determined by variable-temperature 1H-NMR spectroscopy, thus reflecting different degrees of B=N double bond character in the corresponding compounds. In addition, ring external olefin isomers 11 were obtained by a reaction between 2 and DurBBr2. All obtained B=N-containing products were characterized by multinuclear NMR spectroscopy. Compounds 5, 9, 10a, 11, and 13a were also characterized by single-crystal X-ray diffraction analysis.

Electric-field-controlled magnetic anisotropy in ferromagnetic/PMN-PT multiferroic heterostructure attracts great interest due to its promising application for energy-efficient information storage. Herewith, we investigate the effect of ferroelectric polarization and interfacial oxidation on magnetic anisotropy in Fe4N/PMN-PT multiferroic heterostructure using first-principles calculations. The reversal of ferroelectric polarization produces a sizable increase in the perpendicular magnetic anisotropy of Fe4N/PMN-PT heterostructures while the interfacial oxidation changes the sign of the magnetic anisotropy. The modulation of magnetic anisotropy in Fe4N/PMN-PT heterostructure is attributed to the spin–orbit-coupled Pb p  states induced by the magnetoelectric coupling effect. These results lay the foundation for realizing electric-field control of perpendicular magnetic anisotropy in multiferroic heterostructures. [ABSTRACT FROM AUTHOR]

The electronic structure of monolayer MoS2, WS2, MoSe2 and WSe2 on top of antiferromagnetic MnO(1 1 1) is investigated systematically by first-principles calculations. It is found that termination of the MnO substrate can switch the spin splitting of monolayer MoS2, WS2, MoSe2 and WSe2. The spin splitting of MoS2/MnO for six possible interface configurations is varied from 24 to 291 meV for the K point, and 18 to 253 meV for the Kʹ point. The pattern of stacking also induces p - or n-type doping of MoS2, revealing that the conductivity of the heterostructures could be tuned by stacking on MnO. In addition, we also calculate electronic structures of WS2/MnO, MoSe2/MnO and WSe2/MnO heterostructures in the Mn-terminated (III) configuration, and find that the spin splitting at the K point is 553, 324 and 481 meV, and 215, 9 and 284 meV for the Kʹ point, respectively. Furthermore, the time-reversal symmetry is broken by the stacking on MnO that leads to the valley polarization. The valley splitting of MoS2/MnO, WS2/MnO, MoSe2/MnO and WSe2/MnO is 161, 193, 171 and 125 meV in the Mn-terminated (III) configuration. The results present a new type of novel heterostructure that has potential applications in spintronic and valleytronic devices. [ABSTRACT FROM AUTHOR]

The microstructure and high frequency properties of facing-target sputtered epitaxial γ′-Fe4N films were investigated in detail. It was found that the eddy current in ultrathin γ′-Fe4N films is too small to influence the ferromagnetic resonance (FMR) linewidth, where the linewidth is mostly determined by intrinsic damping and the two-magnon scattering (TMS) process. In relatively thick films, the TMS process can significantly affect the linewidth due to the roughness on the sample surface. However, the TMS process in a thin film is quite weak because of its smooth surface. The Gilbert damping constant of about 0.0135 in our γ′-Fe4N films is smaller than the experimental value in the previous work. Moreover, substrates can also influence the FMR linewidth of the γ′-Fe4N films by the TMS process. Besides, the resonance field of polycrystalline γ′-Fe4N film is larger than the epitaxial ones because of the lack of a magnetic anisotropic field, but the linewidth of the polycrystalline γ′-Fe4N film is smaller. [ABSTRACT FROM AUTHOR]

As a research upsurge, van der Waals (vdW) heterostructures give rise to numerous combined merits and novel applications in nanoelectronics fields. Here, we systematically investigate the electronic structure of MnPSe3/CrSiTe3 vdW heterostructures with various stacking patterns. Then, particular attention of this work is paid on the band structure modulations in MnPSe3/CrSiTe3 vdW heterostructures via biaxial strain or electric field. Under a tensile strain, the relative band edge positions of heterostructures transform from type-I (nested) to type-II (staggered). The relocation of conduction band minimum also brings about a transition from indirect to direct band gap. Under a compressive strain, the electronic properties change from semiconducting to metallic. The physical mechanism of strain-dependent band structure may be ascribed to the shifts of the energy bands impelled by different superposition of atomic orbitals. Meanwhile, our calculations manifest that band gap values of MnPSe3/CrSiTe3 heterostructures are insensitive to the electric field. Even so, by applying a suitable intensity of negative electric field, the band alignment transition from type-I to type-II can also be realized. The efficient band structure modulations via external factors endow MnPSe3/CrSiTe3 heterostructures with great potential in novel applications, such as strain sensors, photocatalysis, spintronic and photoelectronic devices. [ABSTRACT FROM AUTHOR]