Metallic Behavior Research Articles

Earthworm mucus contributes significantly to the accumulation of soil cadmium in tomato seedlings

Whether earthworm mucus affects Cd transport behavior in soil-plant systems remains uncertain. Consequently, this study thoroughly assessed the impacts of earthworm mucus on plant growth and physiological responses, plant Cd accumulation, translocation, and distribution, as well as soil characteristics and Cd fractionation in a soil-plant (tomato seedling) system. Results demonstrated that the earthworm inoculation considerably enhanced plant Cd uptake and decreased plant Cd translocation, the effects of which were appreciably less significant than those of the earthworm mucus. This suggested that earthworm mucus may play a crucial role in the way earthworms influence plant Cd uptake and translocation. Moreover, the artificial mucus, which contained identical inorganic nitrogen contents to those in earthworm mucus, had no significant effect on plant Cd accumulation or translocation, implying that components other than inorganic nitrogen in the earthworm mucus may have contributed significantly to the overall effects of the mucus. Compared with the control, the earthworm mucus most substantially increased the root Cd content, the Cd accumulation amount of root and whole plant, and root Cd BCF by 93.7 %, 221.3 %, 72.2 %, and 93.7 %, respectively, while notably reducing the Cd TF by 48.2 %, which may be ascribed to the earthworm mucus's significant impacts on tomato seedling growth and physiological indicators, its considerable influences on the subcellular components and chemical species of root Cd, and its substantial effects on the soil characteristics and soil Cd fractionation, as revealed by correlation analysis. Redundancy analysis further suggested that the most prominent impacts of earthworm mucus may have been due to its considerable reduction of soil pH, improvement of soil DOC content, and enhancement of the exchangeable Cd fraction in soil. This work may help better understand how earthworm mucus influences the transport behavior of metals in soil-plant systems.

Room temperature deposited highly conductive HfNx films for high-performance HfN/Si junction diodes

Transition metal nitrides are valuable materials for many technological applications due to their favorable physical characteristics, including conductivity, high temperature stability, and hardness. Among them, hafnium nitride (HfN) thin films of high attributes are crucial for semiconductor applications. However, achieving performance efficiency of HfN films with desired electrical performance via conventional deposition methods is a challenging task. Herein, we have achieved room temperature growth of highly oriented cubic HfN thin film grown on Si substrate by process optimization of radio frequency (RF) magnetron sputtering. HfN thin films were structurally, morphologically, and electrically characterized. The metallic behavior of HfN films was confirmed through current-voltage measurements; it showcased excellent electrical conductivity, signifying low resistivity (≈ 0.55 kΩ sq-1), revealing promising evidence for its potential practical application. Moreover, the first-principles calculations were also conducted to gain further insights into the electrical performance of the HfN films. These findings lay a solid foundation for further exploration and development of HfN-based junction diodes, as the observed characteristics offer significant potential for enhancing device performance in various electronic domains.

Weak antilocalization in the topological semimetal candidate YbAuSb

We report a study of the magnetic and magnetotransport properties of YbAuSb single crystals, which were grown using the bismuth flux. The x-ray diffraction data indicate that YbAuSb crystallizes in LiGaGe-type hexagonal structure with space groupP63mc. Our magnetic measurements revealed that YbAuSb is nonmagnetic with a divalent state of ytterbium ion. The temperature-dependent electrical resistivity exhibits a metallic behavior. A cusp-like feature in transverse and longitudinal magnetoresistance is observed at the low field regime. This cusp-like feature is attributed to the weak antilocalization (WAL) effect, which is more prominent at low temperatures. The transverse magnetoconductivity in low field region follows semiclassical model∼B, which is consistent with the presence of WAL phenomena. The WAL effect in transverse and longitudinal magnetoconductance is well explained using the modified Hikami-Larkin-Nagaoka and generalized Altshuler-Aronov model, respectively. The Hall resistivity shows a linear field dependence with a positive slope, suggesting hole charge carriers dominate in electrical transport. The calculated carrier density and mobility are in the order of 1020 cm-3and 102 cm2 V-1 s-1, respectively.

Integration of vanadium diphosphide with 2D cobalt phosphide architected as an extensible redox active positrode for alkaline supercapacitor

Metal phosphides in the form of rationally constructed two-dimensional (2D) nanosheets hold significant promise as versatile materials for energy storage applications. This study introduces a novel hybrid supercapacitor electrode, composed of a binder-free vanadium phosphide integrated cobalt phosphide (VP@CP) on a nickel foam substrate. The fabrication process involves the hydrothermal growth of Co2(OH)2BDC (BDC- 1,4-benzenedicarboxylate) nanosheets on a Ni-foam substrate (CMF-Ni), followed by the deposition of VO2 on CMF nanosheets (VO@CMF-Ni) using chronoamperometry and phosphorization of the VO@CMF-Ni to yield VP@CP-Ni nanosheets. Particularly, the density functional theory (DFT) results show that the VP2 integrated Co2P sample provides metallic behavior and low adsorption energy of OH− ions, resulting in improved electrochemical redox process. These bimetallic phosphides exhibit outstanding properties, including enhanced pathways for rapid ion transport and storage, increased electronic conductivity, and expanded electroactive regions facilitating the faradaic charge storage process. Due to the presence of vanadium and cobalt coupled sites, the fabricated VP@CP-Ni electrode was able to attain a maximum areal capacity (CAR) of 971 mA h cm−2 at 6 mA cm−2. Additionally, the fabricated hybrid device (HDC) exhibits an impressive specific energy (SE) of 30.9 Wh kg−1 at a specific power (SP) of 1344 W kg−1, and excellent cyclic durability. These remarkable results stimulate the exploration of such possible 2D VP@CP-Ni nanosheets with promising charge storage electrode capabilities to develop a future era of energy storage devices.

Oxygen Vacancy Controlled Hyperbolic Metamaterial Based on Indium Tin Oxide (ITO) Nanotubes with Switchable Optical Properties

AbstractNanostructured metamaterials can offer optical properties beyond what is achievable in conventional media, such as negative refraction or sub‐wavelength imaging. Due to their structural anisotropy, the class of high aspect ratio metamaterials is of interest for the possibility of achieving hyperbolic optical properties, i.e., both metallic and dielectric behavior based on the excitation direction. Although investigated numerically, the fabrication of tailor‐made metamaterials is complex or often beyond the reach of current technology. For wire metamaterials composed of aligned metallic nanowires in a dielectric matrix, since the free carrier concentration in metals is fixed, light‐matter interaction cannot be adjusted after fabrication. Here, metamaterials based on plasmonic ITO nanotubes with controllable hyperbolic response are introduced. The synthesis is achieved by a template‐based liquid‐phase technique. The tuning mechanism is based on controlling the carrier density in ITO via oxygen vacancy concentration. The process is reversible, the photonic features are activated by creating oxygen vacancies and can be switched off by filling them up again. Further, it is shown that the carrier concentration can also be controlled via a static electric field. Optical simulations support the experimental findings and highlight the parameters that determine the optical response of the metamaterial.

Investigation on the structural, elastic, electronic, thermodynamic, and vibrational properties of the full heusler Sc2XAl (X =Cd and Zn): An ab initio study

The structural, mechanical, electronic, thermodynamic, and phonon characteristics of Sc2CdAl and Sc2ZnAl in L21 phase were the main focuses on this investigation. The density of states (DOS) and electronic band spectra signify the metallic behavior of the L21 phase of both materials. The impact of atomic arrangement with respect to the Wyckoff sites on the mechanical stability were additionally studied. The elastic constants of Sc2CdAl and Sc2ZnAl alloys indicated that these alloys convened Born mechanical stability criteria. Using the density functional perturbation theory's first-principle linear response method, complete phonon spectra have been acquired. Moreover, the quasi-harmonic approximation, specific heat capacity at constant volume, the internal free energy, entropy, and vibrational free energy variations of Sc2CdAl and Sc2ZnAl as full Heusler alloys have been utilized in examination the change over the temperature between 0 and 800 K. Both alloys might find application in real industrial applications.

Immobilization of heavy metals with chlorine and liquid phase formation during thermal treatment of MSWI fly ash

Due to effective detoxification, thermal treatment is a preferred treatment technology of municipal solid waste incineration (MSWI) fly ash. However, immobilization behavior of heavy metals during thermal treatment is unclear. In this work, a circulated fluidized bed fly ash with SiO2 addition and a grate furnace fly ash with high silica-aluminum coal ash addition were used to investigate combined effect of active chlorine content, liquid polymerization degree, temperature of initial liquid phase formation and liquid phase formation rate on the immobilization ratios of Zn, Pb and Cd by principle component analysis (PCA). The results show that the decrease in active chlorine content favors the immobilization of Zn, Pb and Cd because chlorination volatilization is reduced. Both the increase in liquid polymerization degree and the formation of initial liquid phase at low temperature promote the immobilization of Zn, Pb and Cd for physical encapsulation. However, a rapid formation of liquid phase is not favorable for the immobilization of Zn, Pb and Cd, because transfer of heavy metals between crystals and liquid phase is impeded by high viscosity of liquid phase during fusion. The results can provide a reference for how to achieve the immobilization of heavy metals by adjusting the chemical composition of MSWI fly ash during thermal treatment.

Transforming contaminant ligands at water–solid interfaces via trivalent metal coordination

In environmental matrices, the migration and distribution of contaminants at water–solid interfaces play a crucial role in their capture or dissemination. Scientists working in environmental remediation and wastewater treatment are increasingly aware of metal–contaminant coordination; however, interfacial behaviors remain underexplored. Here, we show that trivalent metal ions (e.g. Al3+ and Fe3+) mediate the migration of pollutant ligands (e.g. tetracycline (TC) and ofloxacin) to the organic solid interface. In the absence of Al3+, humic acid (HA) colloids (50 mg/L) capture 26.1 % of the TC in water (initial concentration: 10 mg/L) via weak intermolecular interactions (binding energy: −5.71 kcal/mol). Adding Al3+ (2.5 mg/L) significantly enhances the binding of TC to an impressive 94.2 % via Al3+ mediated coordination (binding energy: −84.89 kcal/mol). The significant increase in binding energy results in superior interfacial immobilization. However, excess free Al3+ competes for TC binding via direct binary coordination, as confirmed based on the unique fluorescence of Al3+–TC complexes. Density functional theory calculations reveal the intricate process of HA–Al3+ binding via carboxyl and phenolic hydroxyl sites. The HA–Al3+ flocs then leverage the remaining coordination capacity of Al3+ to chelate with TC. As well as providing insights into the pivotal role of metal ion on the self-purification of natural water bodies, our findings on the interfacial behavior of metal–contaminant coordination will propel coagulation technology to the capture of microscale pollutants.

Comparative bioengineering and optoelectronic properties of metoprolol by DFT, molecular docking, and molecular dynamic approaches

The biophysical properties of metoprolol are investigated by the full potential-linearized augmented plane wave method and molecular docking and molecular dynamic approaches. The exchange–correlation potentials are calculated by the Perdew–Burke–Ernzerhof generalized gradient approximation as implemented in the WIEN2k package. The electronic results show the insulator nature of metoprolol with the indirect bandgap of 3.74 eV between HOMO and LUMO states. In the density of state spectra, the p state of O, C, and N elements confirm the stability of metoprolol. Metoprolol exhibits a metallic behavior in the z direction, while it has a dielectric behavior in the x and y directions. The static refractive indices are obtained 1.49, 1.53, and 1.63 in the x, y, and z directions, respectively. It was found that the maximum reflectivity occurs at the ultraviolet region in the z-direction. The calculated absorption spectra also confirm the other’s experimental results. The obtained results of molecular docking indicate the formation of hydrogen bonds between metoprolol and the beta-2 adrenergic receptors, and molecular dynamics showed a human beta-2 adrenoceptor either in its free state or in complex with a metoprolol molecule. The calculated binding energies of elements by molecular docking and the other biological properties of metoprolol by molecular dynamic are in close agreement with obtained Density Functional Theory (DFT) results for Pharmacia applications.

First-principles Study on Structural and Electronic Properties: The Li Based of Full-Hesulter Alloys LiGa2Ir

Abstract: Due to their excellent electronic properties, full-Heusler compounds have become one of the most interesting families of alloys in superconductivity. More recently, computational methods have been actively employed to support the rapid discovery of new complete Heusler alloys by identifying stable compositions with desired properties. Therefore, we investigated the stability, structure, and electronic properties of the lithium-based Heusler compound LiGa2Ir using first-principles calculations. We explored the effects of exchange-correlation, namely Perdew-Burke-Ernzerhof (PBE), PBE+U, and Tran-Blaha modified Becke-Johnson potentials, as well as the effect of heavy metal spin-orbit coupling on these Heusler compounds. The results show that LiGa2Ir is energetically stable, and the obtained lattice parameter value (a = 6.0927 Å) agrees with the experimental results. LiGa2Ir exhibits metallic behavior under all three exchange-correlation estimates. A much stronger spin-orbit coupling effect is observed for electronic states with energies below the Fermi level EF, especially in the Tran-Blaha modified Becke-Johnson approximation. Significant spin-orbit coupling effects are evident from the total and partial density of states figures, especially in the energy range from -4.5 eV to -2 eV. The contributions from Ir-d and Ga-p orbitals are the largest, while the contribution from the Li atom is small. Our findings will benefit future theoretical and practical work on lithium-based full-Heusler alloys. Keywords: Full-Heusler, DFT, Spin-orbit coupling, Electronic properties, Density of states.

Neural network based rYld2004 anisotropic hardening model under non-associated flow rule for BCC and FCC metals

This paper extends the reduced Yld2004 (rYld2004) function to present the anisotropic hardening behavior for body-centered cubic and face-centered cubic metals under the proportional loading conditions based on neural network. The parameters of the rYld2004 anisotropic hardening model (AH_rYld2004) are determined by the uniaxial tensile yield stresses along 0°, 15°, 30°, 45°, 60°, 75° and 90° from the rolling direction as well as equibiaxial tension. The evolution of anisotropic parameters are described by the back propagation neural network optimized by ant colony optimization algorithm. The predicted data by AH_rYld2004 and some common anisotropic models are compared with the experimental results to verify the precision of the AH_rYld2004 in characterizing anisotropic hardening. The comparison proves that the AH_rYld2004 precisely characterize the anisotropic evolution with increasing plastic deformation for AA 3003-O and QP980. Simultaneously, the AH_rYld2004 function based on neural network is used to accurately simulate of circular cup deep drawing for AA 3003-O and uniaxial tension for QP980. The results indicate that the AH_rYld2004 model is capable to accurately represent the plastic anisotropic evolution for uniaxial tension along seven loading directions and equibiaxial tension.

Unlocking the potential: Transforming hazardous waste into solid cementitious materials

Incineration fly ash and mineral slag represent hazardous and industrial solid wastes necessitating immediate remediation in China. The liberation and stabilization of heavy metals have erected formidable barriers to their reclamation and repurposing. This study presents a pivotal technology for creating all-solid waste cementitious materials, with the optimal parameters consisting of a dosage of 55.773% incineration fly ash, 38.822% cementitious materials dosage, and 5.405% adhesive powders dosage. Furthermore, a comprehensive evaluation model has been developed to assess the performance of these materials. Several extraction procedure experiments were conducted to investigate the leaching behavior of heavy metals under various leaching scenarios, which suggests the diffusion coefficients of heavy metals under the optimal ratio are all less than 3 × 10–13 m2/s, affirming the effective stabilization and the absence of potential migration risks. The primary mechanisms of solidification involved include ion exchange reactions for charge balance and the encapsulation of precipitates through cementation, both of which contribute to the solidification of heavy metals. The findings will illuminate advanced strategies for reducing waste, enhancing resource efficiency, and promoting environmentally friendly building practices, as well as provide a promising avenue for achieving sustainability goals in construction projects, leading to reduced environmental impact and improved long-term sustainability. The integration of ACM-SW can pave the way for transformative advancements in sustainable building practices, ultimately leading to a more environmentally friendly and resilient built environment.

Metallic nature of T-graphene sheet and nanotubes

The band structure, density of states (DOS), and Pauli magnetic susceptibility (PMS) of T-graphene nanotubes (TGNTs) with varying chiralities and diameters are investigated using the tight-binding Hamiltonian model and Green's function formalism. We analyze two edge types: zigzag (zTGNT) and armchair (aTGNT). Our findings reveal that both zTGNTs and aTGNTs exhibit metallic behavior regardless of diameter. Notably, aTGNTs feature Dirac points in their band structure, with their abundance increasing with nanotube diameter. As compared to graphene, when the diameter of the nanotube increases, aTGNTs reveal more Dirac points at the Fermi level. Additionally, increasing the diameter leads to the emergence of additional sub-bands in the band structure and van-Hove singularities in the DOS diagrams. Consequently, the PMS curves exhibit a crossover, dividing into distinct regimes at varying temperatures. The metallic properties of both TGNT types are apparent in the PMS curves, attributed to the proportional relationship between PMS and DOS. Furthermore, the DOS curves converge towards monolayer behavior as the TGNT diameter increases significantly.

Antipolar 2D Metallicity with Tunable Valence Wx+ (5 ≤ x ≤ 5.6) in the Layered Monophosphate Tungsten Bronzes [Ba(PO4)2]WmO3m-3.

The newly discovered series of layered monophosphate tungsten bronzes (L-MPTB) [Ba(PO4)2]WmO3m-3 consist of m-layer-thick slabs of WO6 octahedra separated by barium-phosphate spacers. They display a 2D metallic behavior confined in the central part of the perovskite slabs. Here, we report the missing m = 2 member of this series, containing the rather uncommon W5+ oxidation state. We have analyzed its structure-property relationships in relation to the other members of the L-MPTB family. In particular, we have determined its crystal structure by means of single-crystal X-ray and electron diffraction and investigated its physical properties from resistivity, Seebeck-coefficient and heat-capacity measurements combined with first-principles calculations. All the L-MPTB compounds show metallic behavior down to 1.8 K without any clear charge-density-wave (CDW) order. The m = 2 member, however, displays an increased influence of the spacer that translates into anisotropic negative thermal expansion, reversed thermopower and reversed crystal-field splitting of the tungsten t2g orbitals. Our analysis of the full [Ba(PO4)2]WmO3m-3 series reveals a systematic and significant W off-centering in their octahedral coordination. We identify the resulting anti-polar character of these W displacements as the crucial aspect behind the 2D metallicity of these systems: It leads to the presence of bound charges whose screening determines the distribution of mobile charges, tending to accumulate at the center of the [WmO3-m] block. We argue that this mechanism is analogous to enhanced conductivity observed for charged domain walls in ferroelectrics, thus providing a general design rule to promote 2D metallicity in layered systems.

A comparative study on the slow pyrolysis of Miscanthus (Miscanthus×giganteus Greef et Deu.) cultivated on agricultural and contaminated soils: Assessment of distribution of final products

This study aims to investigate the slow pyrolysis behavior of uncontaminated (MSC-I - reference) and heavy metals contaminated (MSC-R) samples with heavy metals from the tailings of a Pb-Zn-Cu flotation mine, consisting of whole stems of Miscanthus. Physicochemical properties of raw materials were investigated through instrumental characterization techniques (Atomic Absorption Spectrometry (AAS), Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and X-ray diffraction (XRD)), while the pyrolysis process was monitored by simultaneous thermal analysis techniques (thermogravimetry (TG) – derivative thermogravimetry (DTG)), coupled with Mass spectrometry (MS), for evolved gas analysis. After determination of the lignocellulose content (cellulose, hemicellulose, and lignin) and extractive of the MSC-I and MSC-R samples, it was found that Pb, Zn, Fe, and Mn in MSC-R lead to very fast decomposition of extractive fraction, which facilitates their distribution in formed bio-char, together with lignin char-participation, acting catalytically. It was established that a much greater fraction of extractives decomposition products and non-volatile heavy metals are incorporated in MSC-R bio-char increasing its yield (23 %), compared to MSC-I bio-char yield (21.5 %). It was identified that MSC-R has increased production of H2, CO, and CO2, while decreased production of CH4, influenced by Fe (Fe has a significant positive effect on CO2 evaluation during MSC-R pyrolysis, enhancing decarboxylation process). It was established that CH4 reforming reactions catalyzed by iron additionally affect methane reduction, and increase production of H2, compared to the reference sample. Isoconversional kinetic analysis showed that pyrolysis reactions profile was strongly conditioned by the presence of heavy metals, such as Cd, Pb, and Zn, because they affect the modification of biomass lignocellulosic structure. Also, it was found that small amounts of Cd present in MSC-R can increase pyrolysis activation energy of three pseudo-components, and inhibit their deoxygenation, thus increasing yield of bio-char.

Promoting Surface Conduction through Scalable Structure Engineering of Flexible Topological Insulator Thin Films

AbstractSpintronics, micro/nanofabrication, and the semiconductor industry are undergoing significant transformations, highlighting the need for flexible technologie. This study examines the possibility of integrating topological insulators (TIs), specifically Bi2Te3 thin films (13–191 nm), into flexible spintronic applications through scalable magneto‐sputtering techniques, and investigates how structural organization influences electrical and topological properties through post‐thermal annealing. Films annealed above 250 °C display improved polycrystalline structure, larger crystallites, fewer local defects, and higher a room‐temperature Seebeck coefficient (S) and resistivity (ρ), suggesting decreased bulk electronic contributions. A metastable transport regime is identified in the temperature‐dependent resistivity of films annealed at 300 °C between 20–100 K; in this range, the thinnest film exhibits markedly metallic behavior, signaling the presence of topological surface states (TSS). Magnetoresistance measurements of as‐grown and annealed films, between 3–20 K, demonstrate weak antilocalization. Applying the Hikami‐Larkin‐Nagaoka model, α‐coefficients are found to scale with thickness from 0.5–1, indicating thickness‐controlled coupling of the TSS. Post‐annealing at 300 °C, the phase coherence length, Lϕ, of the thinner films increases, while the temperature dephasing rate shifts from ∼0.7 (as‐grown) to ∼0.5 (post‐annealing), aligning with expected values for 2D TSS. These are encouraging findings for large‐scale manufacturing flexible TI technologies, without sacrificing tunabilit.

Assessment of the environmental impacts of utilizing coal ashes and OPC for soil stabilization applications: Leachate analysis in response to rainfall interaction

The construction industry is a leading sector for coal ashes utilization, including in cement manufacturing and soil stabilization applications. In soil stabilization, coal ashes, alongside Ordinary Portland Cement (OPC), are the most commonly used materials. However, the environmental impact of coal ashes, particularly the leaching of heavy metals from stabilized soil when exposed to rainfall, remains underexplored. There is a notable gap in assessing the environmental impacts of this utilization, particularly when the stabilized soil interacts with rainfall in real-world scenarios. Therefore, this study aimed to contribute to filling this gap. Accordingly, in this study, peat soil was stabilized by using fly ash, bottom ash, and OPC. The characterization of soil mixture materials, including physicochemical and engineering properties, was established and studied first. Following the environmental impact, simulations were conducted using a column to study soil leachate under different conditions and seasons (dry and wet) in response to its interaction with rainfall. The leachate was analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to measure the concentrations of heavy metals, including copper (Cu), aluminum (Al), manganese (Mn), iron (Fe), and zinc (Zn). Additionally, Ion Chromatography (IC) was employed to determine the concentrations of major anions, including fluoride (F⁻), chloride (Cl⁻), nitrate (NO₃⁻), phosphate (PO₄³⁻), and sulfate (SO₄²⁻). The findings revealed the complex interaction of the chemical stabilization processes and environmental factors with the leaching behavior of heavy metals and anions, highlighting the significant impact of stabilization on leaching patterns. To conclude, this study provides a valuable contribution to understanding the environmental and engineering implications of utilizing coal ashes in soil stabilization.

Multifractal Characteristics of Gain Structures: A Universal Law of Polycrystalline Strain-Hardening Behaviors

The quantitative relationship between material microstructures, such as grain distributions, and the nonlinear strain-hardening behaviors of polycrystalline metals has not yet been completely understood. This study finds that the grain correlation dimension of polycrystals D is universally equal to the reciprocal of the strain-hardening exponent by experimental research and fractal geometry analysis. From a geometric perspective, the correlation dimension of grains is consistent with that of the equivalent plastic strain field, which represents the correlation dimension of the material manifold. According to the definition of the Hausdorff measure and Ludwik constitutive model, the strain-hardening exponent represents the exponent derived from the Dth root of the measure relationship. This universal law indicates that the strain-hardening behaviors are fractal geometrized and that the strain-hardening exponent represents a geometrical parameter reflecting the multifractal characteristics of grain structures. This conclusion can enhance the comprehension of the relationship between microstructure and mechanical properties of materials and highlights the importance of designing materials with non-uniform grain distributions to achieve desired hardening properties.

Superconductivity and Metallic Behavior in Heavily Doped Bulk Single Crystal Diamond and Novel Transportation Behavior at Graphene/Diamond Heterostructure

AbstractOwing to extremely large bandgap of 5.5 eV and high thermal conductivity, diamond is recognized as the most important semiconductor. The superconductivity of polycrystalline diamond has always been reported, but there are also many controversies over the existence of superconductivity in bulk single crystal diamond. Besides, it remains a question whether a metallic state exists for such a large bandgap semiconductor. Herein, a single crystal superconducting diamond with a Hall carrier concentration larger than 3 × 1020 cm−3 is realized by co‐doped of boron and nitrogen, with an extremely low resistivity of 2.07 × 10−3 Ω cm at room temperature and dominated acceptor–donor bounded exciton photoluminescence. Furthermore, it is shown that diamond can transform from superconducting to metallic state under similar carrier concentration with tuned carrier mobility degrading from 9.10 cm2 V−1 s−1 or 5.30 cm2 V−1 s−1 to 2.66 cm2 V−1 s−1 or 1.34 cm2 V−1 s−1. Through integrating graphene on a nitrogen and boron heavily co‐doped diamond, a novel transportation behavior in the monolayer graphene similar with superconducting behavior is realized through combining Andreev reflection and exciton‐mediated superconductivity, which may reveal more interesting superconducting behavior of diamond.

Long-term agricultural reuse of treated wastewater and sewage sludge: developing a Time to Critical Content Index for metal species

This study evaluates the sustainability of spreading wastewater or sewage sludge on agricultural land, balancing benefits with contamination risks. Conventional ecological risk indices often fail to address the long-term accumulation of metals in soils. We investigate the feasibility of spreading based on current knowledge of potentially contaminating metals and their behavior in soil. We analyzed the speciation of metals (Ag, Cd, Co, Cr, Cu, Ni, Pb, Ti, Zn) through sequential extraction in sludge, treated wastewater, and soils after 14 years of application of sewage sludge and treated wastewater issued from an Algerian wastewater treatment plant. We introduce a Time to Critical Content Index (TCCI) that calculates the time required to reach critical levels of potentially mobile metals, considering total metal content and speciation. The TCCI takes into account product knowledge, soil characteristics, metal behavior, ecological/toxicological thresholds, and regulations. Applied to our case study, the TCCI indicates that spreading sewage sludge can continue despite metal contents exceeding regulatory ceiling values. The index serves as a precautionary measure, adaptable to evolving knowledge, providing a comprehensive framework for sustainable agricultural practices.Graphical