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Magnetism in monolayer InSe by nonmetal doping: First-principles study
摘要： To develop InSe-based spintronics devices, introducing magnetism into monolayer InSe is essential. In this work, the electronic and magnetic properties of nonmetal (NM) doped (H, B, C, Si, N, P, As, O, S, Te, F, Cl, Br and I) monolayer InSe were investigated by first-principles calculations. The results indicate that atoms from VA, VIA and VIIA groups are possible to substitute Se atoms under In-rich condition. Second, we have found that only the InSe doped with NM acceptors with odd number of valence electrons possesses magnetism. Especially B doped InSe is a half-metal. However, VIIA group doped InSe does not exhibit magnetism due to the In-In covalent bond. This work provides an important guidance for developing spintronic devices on monolayer InSe.
关键词： nonmetal doping,Monolayer InSe,magnetism,half-metal,In-In covalent bond
更新于2025-09-10 09:29:36
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Probing the Electronic Properties of Monolayer MoS <sub/>2</sub> via Interaction with Molecular Hydrogen
摘要： This work presents a detailed experimental investigation of the interaction between molecular hydrogen (H2) and monolayer MoS2 field effect transistors (MoS2 FET), aiming for sensing application. The MoS2 FET exhibits a response to H2 that covers a broad range of concentration (0.1–90%) at a relatively low operating temperature range (300–473 K). Most important, H2 sensors based on MoS2 FETs show desirable properties such as full reversibility and absence of catalytic metal dopants (Pt or Pd). The experimental results indicate that the conductivity of MoS2 monotonically increases as a function of the H2 concentration due to a reversible charge transferring process. It is proposed that such process involves dissociative H2 adsorption driven by interaction with sulfur vacancies in the MoS2 surface (VS). This description is in agreement with related density functional theory studies about H2 adsorption on MoS2. Finally, measurements on partially defect-passivated MoS2 FETs using atomic layer deposited aluminum oxide consist of an experimental indication that the VS plays an important role in the H2 interaction with the MoS2. These findings provide insights for future applications in catalytic process between monolayer MoS2 and H2 and also introduce MoS2 FETs as promising H2 sensors.
关键词： hydrogen gas sensor,gas interaction,hydrogen detection,monolayer MoS2,field effect transistors
更新于2025-09-10 09:29:36
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Pd-doped MoS2 monolayer: A promising candidate for DGA in transformer oil based on DFT method
摘要： Density functional theory (DFT) method was carried out to simulate the adsorption of three dissolved gases on Pd-doped MOS2 (Pd-MoS2) monolayer. We initially studied the possible structures of Pd-MoS2 monolayer and found that the Pd dopant preferred to be adsorbed onto the surface by TMo site. The adsorption and desorption performance, along with the sensing principle of Pd-MoS2 towards three typical gases, including H2, CH4 and C2H2, were analyzed. These analysis indicated that Pd-MoS2 could be a satis?ed material for C2H2 and H2 sensing at speci?c condition; while it is unsuitable for detection of CH4 due to the weak interaction and extremely short recovery time. All these give a ?rst insight into the application of Pd-MoS2 for DGA, evaluating the working operation of the transformer through sensitive detection of H2 and C2H2. We are hopeful that this work would support informative knowledge for experimentalists to realize the potential of Pd-MoS2 in the ?eld of electrical engineering in the near future.
关键词： DGA,Transformer oil,DFT,Pd-MoS2 monolayer
更新于2025-09-10 09:29:36
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Temperature dependence of the dielectric function of monolayer MoS2
摘要： An analytic expression of the dielectric function of monolayer molybdenum disulfide (MoS2) ε = ε1 + iε2 is presented for energies from 1.4 to 6.0 eV and temperatures from 35 to 350 K. The dielectric function parametric model is used to express ε as a sum of polynomials, which naturally includes asymmetry of critical-point lineshapes. The temperature dependence is achieved by fitting model parameters. In this way the dielectric function of MoS2 for arbitrary temperature can be calculated. We observed the fundamental absorption peak, which occurs at the K point of the Brillouin zone. These results are expected to be useful in designing and understanding applied-device technologies based on monolayer MoS2.
关键词： Monolayer MoS2,Ellipsometry,Dielectric function parametric model,Dielectric function
更新于2025-09-10 09:29:36
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Tensile mechanical properties and fracture behavior of monolayer InSe under axial tension
摘要： Based on a newly developed interatomic potential, the mechanical properties and fracture behavior of monolayer InSe are investigated by using the classical molecular dynamics method. We ?nd that monolayer InSe exhibits excellent mechanical properties comparing with other two-dimensional materials. Especially, it can sustain an axial tensile strain of 27% in the zigzag direction at room temperature 300 K. Furthermore, the numerical results indicate that the monolayer InSe has an isotropy in the mechanical behaviors with the Youngs modulus being about 43 N/m both in the armchair and zigzag directions. We also discuss the e?ects of temperature and strain rate on the mechanical properties of monolayer InSe and ?nd the high temperature-sensitivity. It’s found that the mechanical properties signi?cantly decrease as the increasing temperature. In contrast, the mechanical properties has a relatively weak dependence on the strain rate. As the strain rate increases from 0.0002 to 0.0008 ps?1, Young’s modulus nearly keeps a constant. The fracture stress and strain in armchair direction only increase by 3.6% and 8.3%, respectively.
关键词： Tensile strain,Monolayer InSe,Molecular dynamics simulation,Two-dimensional materials,Mechanical property
更新于2025-09-10 09:29:36
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Penta-AlN2 monolayer: A ferromagnetic insulator
摘要： A ferromagnetic insulating behavior is necessary to realize quantum anomalous Hall effect. Here we study, using first-principles calculations and a Monte Carlo simulation, the electronic structure and magnetism of AlN2 monolayer. Our results show that the AlN2 monolayer has a ferromagnetic insulating behavior. By using the crystal field analysis, we find that the axes of the neighboring N2 dimers are perpendicular, and the superexchange between them accounts for the ferromagnetic (FM) order in the AlN2 monolayer. We also carried out a Monte Carlo simulation, which shows that the AlN2 monolayer remains FM with Curie temperature (Tc) ~ 22 K. Moreover, the tensile strain would make a stronger overlap between the neighboring N2 dimers, and steadily enhances the FM stability. As a result, the Tc can be increased with the tensile strain.
关键词： tensile strain,ferromagnetic insulator,AlN2 monolayer,superexchange,quantum anomalous Hall effect
更新于2025-09-10 09:29:36
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Increased yield of MoS <sub/>2</sub> monolayer exfoliation through the bimetallic corrosion of aluminum
摘要： In this paper, we propose a corrosion assisted exfoliation method as an improvement to the traditional tape exfoliation to obtain transition-metal dichalcogenide monolayers. Our method primarily relies on the electrochemical potential difference between transition metals and aluminum. The assistance of bubbles resulting from the bimetallic corrosion increases the yield of the exfoliation process for monolayers by 30-fold while boosting the probability of obtaining isolated monolayers. We use Raman measurements and a statistical comparison of the improved method with tape exfoliation to lay the evidence for our findings.
关键词： transition-metal dichalcogenides,MoS2,bimetallic corrosion,monolayer exfoliation,aluminum
更新于2025-09-10 09:29:36
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Polyphenol-Assisted Exfoliation of Transition Metal Dichalcogenides into Nanosheets as Photothermal Nanocarriers for Enhanced Antibiofilm Activity
摘要： Transition metal dichalcogenides (TMDs) nanosheets have evoked enormous research enthusiasm and have shown increased potentials in biomedical field. However, a great challenge lies in high-throughput, large-scale and eco-friendly preparation of TMDs nanosheets dispersions with high quality. Herein, we report a universal polyphenol-assisted strategy to facilely exfoliate various TMDs into monolayer or few-layer nanosheets. By optimizing the exfoliation condition of molybdenum disulfide (MoS2), the yield and concentration of as-exfoliated nanosheets is up to 60.5% and 1.21 mg/mL, respectively. This is the most efficient aqueous exfoliation method at present and is versatile for the choices of polyphenols and TMDs nanomaterials. The as-exfoliated MoS2 nanosheets possess superior biomedical stability as nanocarriers to load antibiotic drug. They show high photothermal conversion effect and thus induce a synergetic effect of chemotherapy and photothermal therapy to harvest enhanced antibiofilm activity under near-infrared (NIR) light. All these results offer an appealing strategy toward the synthesis and application of ultrathin TMDs nanosheets, with great implications for their development.
关键词： monolayer nanosheets,aqueous exfoliation,photothermal nanocarrier,transition metal dichalcogenides (TMDs),antibiofilm activity
更新于2025-09-10 09:29:36
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Thermoelectric performance of monolayer InSe improved by convergence of multivalley bands
摘要： We theoretically investigate a possibility of improving the thermoelectric performance of monolayer InSe through convergence of multivalley energy bands, in which some distinct valleys become almost degenerate. The convergence of energy bands is achieved by applying mechanical strain. We find that the thermoelectric power factor of monolayer InSe can be significantly enhanced by nearly a factor of 3 through the band convergence in both valence (p-type) and conduction (n-type) bands under a biaxial compressive stress of about 1.16 GPa. However, the maximum enhancement of the figure of merit ZT in the p-type and n-type InSe differs each other depending on how the valleys converge in each case. The optimal scenario is that the heavy valleys approach the light valleys in the band convergence, which leads to an increase in the power factor and, at the same time, a decrease in the thermal conductivity of an electron. This optimal condition can be obtained in the strained n-type InSe that gives the largest enhancement of ZT as high as 230% ZT of unstrained InSe. In contrast, the enhancement of ZT in the strained p-type InSe, which exhibits opposite valley convergence (light valleys joining heavy ones), gives only 26% ZT of unstrained InSe.
关键词： mechanical strain,thermoelectric performance,power factor,figure of merit,multivalley bands,monolayer InSe
更新于2025-09-10 09:29:36
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[IEEE 2018 Open Innovations (OI) - South Africa (2018.10.3-2018.10.5)] 2018 Open Innovations Conference (OI) - Effect of Dipole Corrections and Spin Orbit Coupling on Tungsten Dichalcogenides Monolayer: A in Silico First Principles Study
摘要： The structural and electronic properties of tungsten dichalogenides compounds (WS2, WSe2, WTe2) were investigated from first principles calculations. We found that the structural and electronic properties changed both as a function of the dipole corrections and spin-orbit coupling (SOC). Comparing the calculated results with experimental values, we found that introducing SOC in these 2D materials grossly underestimates the electronic band gap. Adding the self-consistent dipole correction results in larger electronic band gap for these tungsten dichalogenide compounds. Thus, the influence of dipole corrections in these 2D WX2 materials was found to be significant. The SOC are not relevant for these materials and care should be taken on application of these dipole corrections itself.
关键词： tungsten dichalogenides,spin orbit coupling,monolayer,dipole correction
更新于2025-09-09 09:28:46