Effect Of Electric Field Research Articles

Phonon dispersion of quantum paraelectric SrTiO3 in electric fields

Here we report on an elastic and inelastic neutron scattering study addressing the effect of electric fields on quantum paraelectric SrTiO3. Our elastic scattering results find small changes as a function of field in a superlattice reflection that sample the octahedral rotations, which is indicative of only weak coupling of octahedral rotation and electric polarization. Using inelastic neutron scattering, we measured the dispersion of the transverse acoustic and transverse optic phonon in SrTiO3 as a function of applied electric fields. By collecting not only the change in gap, but also of the dispersion, we can better quantify the changes in the lattice dynamics. The findings are put in context to recent DFT calculations predicting the E-field effect on the atomic motions of the lowest lying transverse optical (soft) mode. We find hints of nonlinear coupling to the acoustic mode and to the phonon with polarization perpendicular to the E field, which shows the nonlinearity in the chemical potential that is also relevant when SrTiO3 is excited by strong E-field (THz) pulses. Published by the American Physical Society 2024

The effect of constant electric field on the crack growth process of aluminum nanosheet using molecular dynamics simulation

Aluminum nanosheets are a form of Al nanoparticle that have been recently manufactured on an industrial scale and have a variety of uses. Al nanoparticles are extensively used in a variety of sectors, including aerospace, construction, medical, chemistry, and marine industries. Crack propagation in various constructions must be investigated thoroughly for structural design purposes. Cracks in nanoparticles may occur during the production of nanosheets (NSs) or when different mechanical or thermal pressures were applied. In this work, the effect of a continuous electric field on the fracture formation process of aluminum nanosheets was investigated. For this study, molecular dynamics simulation and LAMMPS software were used. The effects of various electric fields on several parameters, including as stress, velocity (Velo), and fracture length, were explored, and numerical data were retrieved using software. The results show that the amplitude of the electric field parameter affected the atomic development of modeled Al nanosheets throughout the fracture operation. This effect resulted in atomic resonance (amplitude) fluctuations, which affected the mean interatomic forces and led the temporal evolution of atoms to converge to certain specified initial conditions. The crack length in our modeled samples ranged from 22.88 to 32.63 Å, depending on the electric field parameter (0.1–1 V/Å). Finally, it was determined that the crack growth of modeled Al nanosheets may be controlled using CEF parameters in real-world situations.

Effect of electric field on high-temperature decarburization of 0.9%C-Fe steel

Effect of electric field on high-temperature decarburization of 0.9%C-Fe steel

Modulation of Polarization in Sliding Ferroelectrics by Introducing Intrinsic Electric Fields.

The emergence of sliding ferroelectricity facilitates low-barrier ferroelectrics in two-dimensional materials, while limited electric polarizations impede practical applications. Herein, we propose an effective strategy to enlarge the polarization by introducing an intrinsic electric field, exemplified by Janus transition metal dichalcogenides (TMDs) with the first-principle calculations. The intrinsic electric field is introduced and regulated by leveraging the electronegativity differences among chalcogens. An improved polarization is achieved in the Janus TeMoS bilayer with a polarization of 1.18 pC/m, a 65% enhancement compared to normal TMD bilayers. Through differential charge density analysis, the inner mechanism is attributed to the effects of intrinsic electric fields on charge redistribution. Furthermore, the feasibility of polarization reversal is determined by evaluating switching barriers and the responses under an electric field. The provided proposal is applicable and available for broader systems and will pave the way for the development of novel electronic devices.

Tuning p‐Band Centers and Interfacial Built‐In Electric Field of Heterostructure Catalysts to Expedite Bidirectional Sulfur Redox for High‐Performance Li–S Batteries

AbstractTransition‐metal compound based heterostructures hold promise but challenge in expediting stepwise sulfur redox because of their inferior adsorption‐catalysis activity and unclear mechanism in Li–S batteries (LSBs). Herein, the p‐band centers and interfacial charge rearrangement of Mo‐doped VS2/MXene heterostructure are tuned through Mo doping and built‐in electric field (BIEF) effect to boost dual‐directional sulfur redox. Experimental and theoretical calculations demonstrate that Mo doping tunes the p‐band center of active S in VS2, shifting it positively toward the Fermi level to enhance the polysulfide adsorption ability and electrocatalytic activity. Whereas BIEF between Mo‐VS2 and MXene accelerates electrons transfer from MXene to Mo‐VS2 surface, generating more electrons accumulation at the surface‐S sites. Their synergy accelerates sulfur‐species conversion by reducing the energy barrier of polysulfide reduction and Li2S oxidation. Ultimately, S/Mo‐VS2/MXene cathode exhibits large initial capacity of 1387 mAh g−1at 0.2 C and stable 500‐cycle long‐term lifespan at 0.5 C. Impressively, the thick S/Mo‐VS2/MXene cathode (S loading: 5.4 mg cm−2, lean electrolyte: 4.5 µL mgsulfur−1) achieves a high areal capacity of 6.44 mAh cm−2 with 91.5% retention for 61 cycles. This work highlights the synergistic strategy of doping engineering and BIEF to tune the p‐band centers and interfacial charge rearrangement for designing high‐performance LSBs.

Exploring the influence of external electric fields on the catalytic pyrolysis of oil shale kerogen molecules

Oil shale is a widely distributed and abundant sedimentary rock that can be converted into shale oil through pyrolysis, providing a supplementary solution to the increasing scarcity of conventional fossil energy. However, the traditional pyrolysis process of oil shale faces problems such as low oil yield, high energy consumption, and poor oil quality. Recent experiments have demonstrated that using an external electric field to catalyze the pyrolysis of oil shale can address these problems. However, due to the complex physical and chemical properties of oil shale and its pyrolysis process, the catalytic mechanisms and effects have not been reasonably explained. To address these issues, this study uses density functional theory to calculate the properties of oil shale molecules under external electric fields of different directions and strengths. The results indicate that at electric field strengths far exceeding experimental conditions, the external electric field does have a certain catalytic effect on oil shale, which varies depending on the molecule. However, at electric field strengths achievable in actual laboratory conditions, the catalytic effect of the electric field on oil shale is not significant. Therefore, the mechanisms revealed by past experiments on the catalytic effects of electric fields on oil shale pyrolysis may be partially flawed. This study not only fills the gap in understanding the mechanisms of external electric field catalysis of oil shale but also provides a theoretical foundation for future applications of electric fields in catalyzing oil shale.

Highly stable planted MXene auxiliary layer for high-performance zinc anode deposition regulation

Aqueous zinc-ion batteries have good application prospects in large-scale energy storage, but severe dendrite behavior hinders their development. This article reports a method of planting MXene on the surface of zinc foil, that is, while mechanically polishing with a high-speed rotating wire brush, MXene solution is added dropwise, and MXene is anchored on the surface of the zinc foil with the help of a certain pressure. The MXene layer under this preparation method is stronger than the traditional self-assembled MXene layer. The MXene layer therefore acts as a physical barrier, protecting the underlying active zinc from damage. At the same time, the good hydrophilicity of the planted MXene layer reduces the concentration gradient of the interfacial electrolyte and redistributes the zinc ion flux. The unique electric field effect of MXene reduces the desolvation energy barrier, improves the transfer kinetics of Zn ions, and promotes the deposition of zinc ions in the (002) crystal plane. Experimental results show that the symmetrical battery prepared by this method can cycle stably for more than 1000 h at 0.8 mA cm−2, while its Zn\\\\Cu asymmetric battery exhibits cycle stability of more than 700 times at 0.5 mA cm−2. While maintaining a high Coulombic efficiency of over 99 %. Full cells assembled from zinc foil anodes and VO2 cathodes protected by a planted MXene layer also demonstrate higher capacity advantages. Therefore, this more stable MXene layer provides a direction for the practical application of zinc metal anodes.

Stationary External Electric Field-Mimicking the Solvent Effect on the Ground-State Tautomerism and Excited-State Proton Transfer in 8-(Benzo[d]thiazol-2-yl)quinolin-7-ol.

The effect of the external electric field on the ground-state tautomerism in 8-(benzo[d]thiazol-2-yl)quinolin-7-ol has been studied by using density functional theory. The compound exists as an enol tautomer (off state) and under the influence of the external electric field a long-range intramolecular proton transfer can occur, placing the tautomeric proton at the quinolyl nitrogen atom (on state). This is a result of the much higher dipole moment of the end keto tautomer and indicates that the external electric field can be used to mimic the implicit solvent effect in tautomeric systems. In the excited state, the further stabilization of the most polar on state leads to a situation when the excited-state intramolecular proton transfer becomes impossible, limiting the intramolecular rotation to the conical intersection region.

Study of the effects of external imaginary electric field and chiral chemical potential on quark matter

The behavior of quark matter with both external electric field and chiral chemical potential is theoretically and experimentally interesting to consider. In this paper, the case of simultaneous presence of imaginary electric field and chiral chemical potential is investigated using the lattice QCD approach with Nf=1+1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$N_f=1+1$$\\end{document} dynamical staggered fermions. We find that overall both the imaginary electric field and the chiral chemical potential can exacerbate chiral symmetry breaking, which is consistent with theoretical predictions. However we also find a non-monotonic behavior of chiral condensation at specific electric field strengths and chiral chemical potentials. The behavior of Polyakov loop in the complex plane is not significantly affected by chiral chemical potential in the region of the parameters considered.

MXene quantum dots decorated g-C3N4/BiOI heterojunction photocatalyst for efficient NO deep oxidation and CO2 reduction

The photocatalytic performance of g-C3N4 is greatly limited by the severe charge recombination due to its s-triazine unit structure. Hence, enhancing the separation of photogenerated carriers is the pivotal factor for high-efficiency photocatalysis of g-C3N4. In this work, we construct a MXene quantum dots (MQDs) decorated BiOI/g-C3N4p-n heterojunction photocatalyst. The interfacial charge separation and transfer are substantially promoted, due to the synergistic effect of the internal electric field (IEF) of BiOI/g-C3N4 heterojunction and strong electron-withdrawing capability of MQDs. Furthermore, the introduction of BiOI with a low band gap and MQDs with large specific areas and rich surface terminals lead to enhanced light absorption and active sites. As a result, the ternary g-C3N4/MQDs/BiOI photocatalyst achieves a much higher NO removal rate of 42.23 % and discharges less NO2 intermediate than the individual and binary ones. Meanwhile, the g-C3N4/MQDs/BiOI photocatalyst also exhibits the most effective CO2 photoreduction, with a CO production rate of 57.8 μmol·g−1·h−1 and a CH4 production rate of 3.6 μmol·g−1·h−1, surpassing all other photocatalysts in this study. In addition, the designed composite photocatalyst shows remarkable stability. The photocatalytic mechanisms are studied by the trapping experiment and in-situ Fourier Transform Infrared (FTIR) Spectra. This work paves a new avenue for enhancing charge separation and thus improving performances of g-C3N4-based photocatalysts by integrating a p-n heterojunction and a co-catalyst, which would accelerate commercial deployment of emerging photocatalysts.

The effects of electric fields and biaxial strain on the structural, electrical, magnetical, and optical properties of bulk and monolayer AgN

The effects of electric fields and biaxial strain on the structural, electrical, magnetical, and optical properties of bulk and monolayer AgN

Influence of the optoelectronic properties of F-MoTe2 systems under the combined action of an external electric field and biaxial tensile-compressive deformation: a first-principles study

The effects of an applied electric field on the electronic structure, charge transfer, and optical characteristics of molybdenum telluride (MoTe2) systems doped with halogen F atoms during biaxial tensile-compressive deformation were explored using first-principles approaches. The results show that the MoTe2 system exhibits an upward shift of the Fermi energy level and a downward shift of the conduction band when crossing the Fermi energy level due to the doping of halogen F atoms. Subsequently, we applied an electric field of −0.4 eV∼−0.4 eV to the F-MoTe2 system. The change of the F-MoTe2 system under the electric field effect is very small. This result indicates that the F-MoTe2 system can be stabilized in this range. Subsequently, we chose to apply a biaxial tensile-compressive deformation of −14%−14% to the F-MoTe2 system under the action of an electric field of +0.4 eV. The F-MoTe2 system underwent a transition from a semiconductor to a metal, with an increase in the carrier concentration and a good shift in electrical conductivity. The compressive strain gives better results than the tensile strain. In terms of optical characteristics, the absorption and emission peaks of the F-MoTe2 system are blueshifted under the combined effect of electric field and stress.

Built-in electric field construction and lattice oxygen activation for boosting alkaline electrochemical water/seawater oxidation

Oxygen evolution reaction (OER) remains a bottleneck for hydrogen production by water-alkali electrolysis at high industrial current density, but the structure–activity relationship of the catalyst and the underlying catalytic mechanism are still debated, which always limits the design of efficient catalysts. Herein, we report a proof-of-concept hierarchical hydroxide/sulfide (NiFe LDH/Ni3S2) heterostructure as model catalyst to simultaneously adjust the electronic states and activate lattice oxygen. As-activated NiFe LDH/Ni3S2 electrode displays promising OER capability with an ultra-low overpotential of 295 mV at the industrial current density of 500 mA·cm−2. The interface-induced built-in electric field effect promotes the asymmetric charge distribution on both sides. In-situ/ex-situ characterization demonstrates the adjusted intermediates adsorption/desorption and accelerated OER kinetics due to rapid electron transfer. A series of electrochemical probe experiments reveal that the OER mechanism of NiFe LDH/Ni3S2 follows the lattice oxygen mechanism. Especially, the super-strong wettability electrode design and structural advantages effectively enhance mass transfer and promote O2 desorption in alkaline water/seawater splitting systems. This work provides an avenue to break through OER limitations for efficient electrocatalytic water oxidation.

Effect of Ti Addition and Electric Field on Microstructure and Mechanical Properties of the Al-Si-Fe Hypereutectic Alloy

Effect of Ti Addition and Electric Field on Microstructure and Mechanical Properties of the Al-Si-Fe Hypereutectic Alloy

Positive impact of surface defects on Maxwell's displacement current-driven nano-LEDs: The application of TENG technology

As the core component of a nanopixel light-emitting display, the GaN-based nanoscale light-emitting diode (nLED) faces the problem of low electroluminescence efficiency resulting from the introduction of surface defects when its lateral size is reduced to the nanometer scale. Thus, reducing the surface defect density is an important direction in nLED-related research. This study, with the triboelectric nanogenerator-driven LED as its inspiration, reveals that surface defects have a positive impact on the performance of nLEDs driven by Maxwell’s displacement current, and we call the related driving mode the noncarrier injection mode. Through finite element simulations, we studied the dynamic variations of the carrier concentration, the energy band, and the light emission rate to analyze the impact of the behavior of surface defect excitation on device performance. We found that surface defects can act as electron pumps under the combined effect of the reverse electric field and the built-in electric field and can generate carriers through surface defect excitation to increase the intensity of noncarrier injection luminescence, which is completely different from the traditional understanding of surface defects. In addition, we propose a tapered structure to further increase the light emission rate by regulating the behaviors of radiation recombination and surface defect excitation. The results of this work open a new perspective on the impacts of surface defects on nLEDs and provide significant information for additional applications of Maxwell's displacement current.

Controllable electrical contact characteristics of graphene/Ga2X3 (X = S, Se) ferroelectric heterojunctions

Reducing the interface barrier between metals and semiconductors is crucial for designing high-performance optoelectronic devices based on van der Waals heterojunctions (HJs). This study proposes four models of HJs composed of graphene (GR) and Ga2X3 (X = S, Se) and systematically investigates their interface electronic properties, along with strain engineering and electric field effects. The results indicated that exploiting the interface dipole-induced potential step allows modulation of the Schottky barrier height (SBH) and contact type of the HJs by altering the contact interfaces. In the BGR/Ga2S3 HJs (BGR means GR positioned at the bottom of Ga2X3), only a small positive (negative) electric field is required to realize the transition from n-type Schottky to p-type Schottky (Ohmic) contacts. Also, strain engineering provides additional means for flexible and controllable contact types, facilitating the design of reversible logic circuits. It indicates the physical insights and strategic interventions of GR/Ga2X3 HJs tunable SBH and offers theoretical guidance for the design of two-dimensional ferroelectric nanodevices with high-quality electrical contact interfaces.

Joule heating for structure reconstruction of hard carbon with superior sodium ion storage performance

Hard carbon anode for sodium ion batteries still remains many challenges including insufficient cycling life and initial Coulombic efficiency (ICE), weak rate capability and poor compatibility in common ester electrolytes. Here, we propose a Joule heating post-treatment including multifield sintering method to reconstruct the structure of hard carbon from thick graphene layers to more disordered vortex layer structure composed of thin and curved graphite-like domains. The molecular dynamics simulation and differential charge density distribution demonstrate the crucial effect of electric field in strengthening the interaction between the polar molecule groups and the graphene layer, leading to the distortion and expanding of graphene layer. This is a universal and highly efficient strategy to modify various hard carbons within minutes. The optimized hard carbon anode exhibits exceptional rate capability and cycling stability with a high retention rate of 88.4% after 15,000 cycles at 10C in ether electrolyte. It also displays remarkably improved reversible capacity, initial Coulombic efficiency ICE of 89.5% and cycling stability in ester electrolyte. It is revealed by in-situ electrochemical impedance spectroscopy and atomic force microscopy that the spontaneous formation of a thin, stable and inorganic substance-rich solid electrolyte interface layer with significantly improved mechanical property is largely responsible for the outstanding sodium-ion transport kinetics and long lifespan.

Boosting electrocatalytic ammonia synthesis from nitrate by asymmetric chemical potential activated interfacial electric fields

The electrocatalytic nitrate reduction reaction (NO3− RR) has immense potential to alleviate the problem of groundwater pollution and may also become a key route for the environmentally benign production of ammonia (NH3) products. Here, the unique effects of interfacial electric fields arising from asymmetric chemical potentials and local defects were integrated into the binary Bi2S3-Bi2O3 sublattices for enhancing electrocatalytic nitrate reduction reactions. The obtained binary system showed a superior Faraday efficiency (FE) for ammonia production of 94 % and an NH3 yield rate of 89.83 mg gcat-1h−1 at −0.4 V vs. RHE. Systematic experimental and computational results confirmed that the concerted interplay between interfacial electric fields and local defects not only promoted the accumulation and adsorption of NO3–, but also contributed to the destabilization of *NO and the subsequent deoxygenation hydrogenation reaction. This work will stimulate future designs of heterostructured catalysts for efficient electrocatalytic nitrate reduction reactions.

Effects of external static electrical field on thermal and electrical conductivity in the Al-Cu, Al-Ni, and Al-Si eutectic alloys

This study aims to investigate the effects of external positive and negative static electric fields (E+ and E- respectively) on thermal conductivity (K) and electrical conductivity (σ) in Al-33 wt. % Cu, Al-6.4 wt. % Ni and Al-12 wt. % Si eutectic alloys. For this purpose, the solidifications of Al-Cu, Al-Ni, and Al-Si eutectic alloys were directionally done under E+ and E-. The directions of E were chosen to be parallel (E+) and antiparallel (E-) to the solid-liquid (S-L) growth direction and the magnitudes of E were approximately (+10) and (−10) kV cm−1 and (+16) and (-16) kV cm−1 for the Al-Cu, Al-Ni, and Al-Si eutectic alloys, respectively. The effects of E+ and E− on the K and σ were determined by the longitudinal heat flow and the four-point probe methods, respectively. While the K and σ values decreased with increasing temperature, the K and σ were increased and decreased with E+ and E−, respectively.

Quantum Theory of Lee–Naughton–Lebed’s Angular Effect in Strong Electric Fields

Quantum Theory of Lee–Naughton–Lebed’s Angular Effect in Strong Electric Fields