Host Atoms Research Articles

Bending-induced enhanced spatial separation of dopants and long-lived conventional nanoribbon p-n junctions.

The spatial separation of dopants is crucial in extending the lifetime of nanoribbon p-n junctions, which is traditionally realized via van der Waals heterostructures at a high cost. In this study, we employ atomistic quantum mechanical simulations to demonstrate that a simple in-plane bending deformation can lead to an enhanced doping preference in conventional nanoribbons. Dopants with larger atomic sizes than those of host atoms tend to reside on the tensile side close to the outermost edge of the bent nanoribbons, while dopants with smaller atomic sizes than those of host atoms tend to reside on the compressive side close to the innermost edge of the bent nanoribbons. We also show that this doping preference induces an enhanced spatial separation of n-type and p-type dopants with different atomic sizes. As conventional nanoribbons are easier to synthesize and cost-effective, our results provide a pathway for modulating dopant distribution and designing long-lived nanoribbon p-n junctions via inhomogeneous strain engineering.

Theoretical study of point defects on transport properties in metallic interconnections

During the line width reduction, electron scattering caused by various defects in metal interconnects increases dramatically, which causes leakage or short circuit problems in the device, reducing device performance and reliability. Point defects are one of the important factors. Here, using density functional theory and non-equilibrium Green's function methods, we systematically study the effects of point defects on the transport properties of metals Al, Cu, Ag, Ir, Rh, and Ru, namely vacancy defects and interstitial doping of C atom. The results show that the conductivity of all systems decreases compared to perfect systems, because defects cause unnecessary electron scattering. Since the orbital hybridization of the C atom with the Al, Cu and Ag atoms is stronger than that metals Ir, Rh and Ru, the doping of C atom significantly reduces the conductivity of metals Al, Cu and Ag compared to vacancy defects. In contrast, vacancy defects have a greater impact than doping on the transport properties of metals Ir, Rh and Ru, which is mainly attributed to the larger charge transfer of the host atoms around the vacancies caused by lattice distortion. In addition, metal Rh exhibits excellent conductivity in all systems. Therefore, in order to optimize the transport properties of interconnect metals, our work points out that the doping of impurity atoms should be avoided for metals Al, Cu and Ag, while the presence of vacancy defects should be avoided for metals Ir, Rh and Ru, and Rh may be an excellent candidate material for future metal interconnects.

Reveal of relationship between microscopy architecture and mechanical performance of Y/Bi substituted Bi-2212 engineering ceramics.

This study aims to find out how the crystallinity quality, surface morphology, and mechanical performances change with the substitution of yttrium (Y) for bismuth (Bi) impurity within molar ratios of 0.00 ≤ x ≤ 0.12 in the Bi2.0-xYxSr2.0Ca1.1Cu2.0Oy (Bi-2212) cuprates to reveal the dependence of micro surface topology on the substitution mechanism and achieve a strong relation between the impurity ions and crystallization mechanism. The materials are prepared by ceramic method. It is found that all the experimental findings improve remarkably with increasing yttrium impurity molar ratio of x = 0.01. Scanning electron microscopy (SEM) images indicate that the optimum Y ions strengthen the formation of flaky adjacent stacked layers due to the changes of thermal expansion, vibration amplitude of atoms, heat capacitance, reaction kinetics, activation energy, nucleation temperature, thermodynamic stability, and intermolecular forces. Besides, new engineering novel compound produced by optimum Y ions presents the best crystallinity quality, uniform surface view, greatest coupling interaction between grains, largest particle size distributions/orientations, and densest/smoothest surface morphology. Hardness measurement results totally support the surface morphology view. Moreover, mechanical design properties and durability of the tetragonal phase improve significantly with increasing replacement level of x = 0.01 due to the induction of new surface residual compressive stress areas, slip systems, and chemical bonding between the foreign and host atoms. Besides, the same sample exhibits the maximum strength and minimum sensitivity to loads depending on reduction of stored internal strain energy and degree of granularity. Consequently, cracks tend to propagate predominantly within the transcrystalline regions. Furthermore, each material investigated exhibits the characteristic behavior of the indentation size effect. In summary, the optimum Y-doped Bi-2212 sample paves the way for the expanded use of engineering ceramics across various applications based on the enhanced service life. RESEARCH HIGHLIGHTS: The presence of the optimum yttrium impurity significantly decreases the Ea value. As the Y/Bi replacement increases up to the molar substitution level of x = 0.01, the mechanical design properties and durability of the tetragonal phase enhance significantly.

Formation energy prediction of neutral single-atom impurities in 2D materials using tree-based machine learning

Abstract We applied tree-based machine learning algorithms to predict the formation energy of impurities in 2D materials, where adsorbates and interstitial defects are investigated. Regression models based on random forest, gradient boosting regression, histogram-based gradient-boosting regression, and light gradient-boosting machine algorithms are employed for training, testing, cross validation, and blind testing. We utilized chemical features from fundamental properties of atoms and supplemented them with structural features from the interaction of the added chemical element with its neighboring host atoms via the Jacobi–Legendre (JL) polynomials. Overall, the prediction accuracy yields optimal MAE ≈ 0.518 , RMSE ≈ 1.14 , and R 2 ≈ 0.855 . When trained separately, we obtained lower residual errors RMSE and MAE, and higher R 2 value for predicting the formation energy in the adsorbates than in the interstitial defects. In both cases, the inclusion of the structural features via the JL polynomials improves the prediction accuracy of the formation energy in terms of decreasing RMSE and MAE, and increasing R 2. This work demonstrates the potential and application of physically meaningful features to obtain physical properties of impurities in 2D materials that otherwise would require higher computational cost.

Donor-induced electrically charged defect levels: examining the role of indium and n-type defect-complexes in germanium

Defect levels induced by defect-complexes in Ge play important roles in device fabrication, characterization, and processing. However, only a few defect levels induced by defect-complexes have been studied, hence limiting the knowledge of how to control the activities of numerous unknown defect-complexes in Ge. In this study, hybrid density functional theory calculations of defect-complexes involving oversize atom (indium) and n-type impurity atoms in Ge were performed. The formation energies, defect-complex stability, and electrical characteristics of induced defect levels in Ge were predicted. Under equilibrium conditions, the formation energy of the defect-complexes was predicted to be within the range of 5.90–11.38 eV. The defect-complexes formed by P and In atoms are the most stable defects with binding energy in the range of 3.31-3.33 eV. Defect levels acting as donors were induced in the band gap of the host Ge. Additionally, while shallow defect levels close to the conduction band were strongly induced by the interactions of Sb, P, and As interstitials with dopant (In), the double donors resulting from the interactions between P, As, N, and the host atoms including In atom are deep, leading to recombination centers. The results of this study could be applicable in device characterization, where the interaction of In atom and n-type impurities in Ge is essential. This report is important as it provides a theoretical understanding of the formation and control of donor-related defect-complexes in Ge.

Investigation of thermal stability improvement in Nb doped Sb2Te3

The phase change material Sb2Te3 (ST) exhibits a fast-switching speed and poor thermal stability because the four-fold rings are dominant and homo-polar bonds are absent in the amorphous state. Many studies have been performed on the improvement of phase change properties. Chemical doping methods have been widely used because additional chemical bonds are formed between the doped element and host atoms, leading to the modification of the local structure and electronic band structure. Previous reports have indicated the importance of the bond length and lattice mismatch in element doped ST. In this study, the electronegativity of the doped elements was investigated because it determines the strength of the bond via charge transfer between two atoms. A strong correlation between the electronegativity of the doped element and the phase change properties of the doped ST was observed. An ideal electronegativity range, which corresponds to some elements doped ST with excellent thermal stability, was found in this investigation. Nb atoms were selected as the optimal dopant to stabilize the amorphous phase of ST because Nb was in the ideal range. Additional homo-polar bonds and Nb-Te bonds can stabilize the amorphous phase because additional energy is required for ring reconstruction during crystallization. Consequently, the thermal stability and resistance difference of the Nb doped ST were significantly improved. In addition, the phase change speed of ST was not affected by Nb doping. This study highlights a new approach for pursuing better properties of phase change materials by chemical doping methods.

Understanding noble gas incorporation in mantle minerals: an atomistic study

Ab initio calculations in forsterite (Mg2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_2$$\\end{document}SiO4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_4$$\\end{document}) are used to gain insight into the formation of point defects and incorporation of noble gases. We calculate the enthalpies of incorporation both at pre-existing vacancies in symmetrically non-equivalent sites, and at interstitial positions. At high pressure, most structural changes affect the MgO6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_{6}$$\\end{document} units and the enthalpies of point defects increase, with those involving Mg and Si vacancies increasing more than those involving O sites. At 15 GPa Si vacancies and Mg interstitials have become the predominant intrinsic defects. We use these calculated enthalpies to estimate the total uptake of noble gases into the bulk crystal as a function of temperature and pressure both in the presence and absence of other heterovalent trace elements. For He and Ne our calculated solubilities point to atoms occupying mainly interstitial sites in agreement with previous experimental work. In contrast, Ar most likely substitutes for Mg due to its larger size and the deformation it causes within the crystal. Incorporation energies, as well as atomic distances suggest that the incorporation mainly depend on the size mismatch between host and guest atoms. Polarization effects arising from the polarizability of the noble gas atom or the presence of charged defects are minimal and do not contribute significantly to the uptake. Finally, the discrepancies between our results and recent experiments suggest that there are other incorporation mechanisms such as adsorption at internal and external interfaces, voids and grain boundaries which must play a major role in noble gas storage and solubility.

Solubility of Hydrogen in a WMoTaNbV High-Entropy Alloy.

The WMoTaNbV alloy has shown promise for applications as a solid state hydrogen storage material. It absorbs significant quantities of H directly from the atmosphere, trapping it with high energy. In this work, the dynamics of the absorption of hydrogen isotopes are studied by determining the activation energy for the solubility and the solution enthalpy of H in the WMoTaNbV alloy. The activation energy was studied by heating samples in a H atmosphere at temperatures ranging from 20 °C to 400 °C and comparing the amounts of absorbed H. The solution activation energy EA of H was determined to be EA=0.22±0.02 eV (21.2 ± 1.9 kJ/mol). The performed density functional theory calculations revealed that the neighbouring host atoms strongly influenced the solution enthalpy, leading to a range of theoretical values from -0.40 eV to 0.29 eV (-38.6 kJ/mol to 28.0 kJ/mol).

Generation of out-of-plane ferroelectric behavior in a one-atom-thick monolayer

Ferroelectricity with out-of-plane polarization has so far been found in several two-dimensional (2D) materials, including monolayers comprising three to five planes of atoms, e.g. α-In2Se3 and MoTe2. Here, we explore the generation of out-of-plane polarization within a one-atom-thick monolayer material, namely hexagonal boron nitride. We performed density-functional-theory calculations to explore inducing ferroelectric-like distortions through incorporation of isovalent substitutional impurities that are larger than the host atoms. This disparity in bond lengths causes a buckling of the h-BN, either up or down, which amounts to a dipole with two equivalent energies and opposing orientations. We tested several impurities to explore the magnitude of the induced dipole and the switching energy barrier for dipole inversion. The effects of strain, dipole–dipole interactions, and vertical heterostructures with graphene are further explored. Our results suggest a highly-tunable system with ground state antiferroelectricity and metastable ferroelectricity. We expect that this work will help foster new ways to include functionality in layered 2D-material-based applications.

Strain-modulated defect engineering of two-dimensional materials

Strain- and defect-engineering are two powerful approaches to tailor the opto-electronic properties of two-dimensional (2D) materials, but the relationship between applied mechanical strain and behavior of defects in these systems remains elusive. Using first-principles calculations, we study the response to external strain of h-BN, graphene, MoSe2, and phosphorene, four archetypal 2D materials, which contain substitutional impurities. We find that the formation energy of the defect structures can either increase or decrease with bi-axial strain, tensile or compressive, depending on the atomic radius of the impurity atom, which can be larger or smaller than that of the host atom. Analysis of the strain maps indicates that this behavior is associated with the compressive or tensile local strains produced by the impurities that interfere with the external strain. We further show that the change in the defect formation energy is related to the change in elastic moduli of the 2D materials upon introduction of impurity, which can correspondingly increase or decrease. The discovered trends are consistent across all studied 2D materials and are likely to be general. Our findings open up opportunities for combined strain- and defect-engineering to tailor the opto-electronic properties of 2D materials, and specifically, the location and properties of single-photon emitters.

Asynchronous propagation of atomic force and excited electronic charge in GaAs under proton irradiation

The studies for the interaction of energetic particles with matter have greatly contributed to the exploration of material properties under irradiation conditions, such as nuclear safety, medical physics and aerospace applications. In this work, we theoretically simulate the non-adiabatic process for GaAs upon proton irradiation using time-dependent density functional theory, and find that the radial propagation of force on atoms and the excitation of electron in GaAs are non-synchronous process. We calculated the electronic stopping power on proton with the velocity of 0.1–0.6 a.u., agreement with the previous empirical results. After further analyzing the force on atoms and the population of excited electrons, we find that under proton irradiation, the electrons around the host atoms at different distances from the proton trajectories are excited almost simultaneously, especially those regions with relatively high charge density. However, the distant atoms have a significant hysteresis in force, which occurs after the surrounding electrons are excited. In addition, hysteresis in force and electron excitation behavior at different positions are closely related to the velocity of proton. This non-synchronous propagation reveals the microscopic dynamic mechanism of energy deposition into the target material under ion irradiation.

Theoretical study of synergistic effect of P and Mg on the cohesive properties of Ni3Al grain boundaries

The addition of specific alloying elements can effectively control the microstructure of alloys, so as to improve the cohesive properties of the GBs. In this work, the first-principles plane-wave pseudopotential method is used to investigate the segregation behavior of P and Mg doping at the Ni3Al GBs and reveal the physical mechanism. Different 100%Ni Σ5 (210) [010] GB systems with and without doping elements are relaxed and larger volume expansions are obtained. The calculated segregation energies show that P or Mg atoms tend to segregate to the GBs relative to the bulk. P atoms tend to stay at the interstitial sites surrounded by 8 Ni atoms in the pure Ni holes of the GBs while Mg atoms tend to substitute Ni atoms. The segregation of P or Mg to the GBs leads to an increase of the Griffith work at the GBs, indicating that the segregation can improve the bonding properties of the GBs. Especially, the synergistic segregation of Mg can improve the detrimental effect of P in the mixed hole on the cohesive properties of the GBs. It is also found that the site occupation of Mg can be reversed from the Ni site to the Al site by the synergistic alloying of P at the 50%Ni Σ5 GBs. P and Mg tend to bond with the host atom Ni regardless of GB structure. The investigation of electronic structure shows that GB strengthening of alloying elements is attributed to the increasing P/Mg-Ni interactions across the GBs.

Functionalization of boron phosphide monolayers for spintronic applications by doping with alkali and alkaline earth metals

In this work, new d 0 magnetic materials are developed by doping boron phosphide (BP) monolayers with alkali (Li, Na, and K) and alkaline earth (Be, Mg, and Ca) metals. First-principles calculations confirm the good dynamical and thermal stability of the pristine monolayer. This two-dimensional model is intrinsically a non-magnetic semiconductor with a band gap of 0.90/1.36 eV, as calculated by the PBE/HSE06 functional. B-P chemical bonds are predominantly covalent, generated by electronic hybridization with a small portion of the ionic character formed by the charge transfer from the B atom to the P atom. Doping with Li, Be, and Mg on the B sublattice preserves the non-magnetic nature, causing either a considerable reduction of the band gap or metallization. Meanwhile, the monolayer is significantly magnetized with a total magnetic moment between 0.94 and 3.86 µ B in the remaining cases. Herein, magnetic properties are primarily produced by p orbitals of impurities and their neighboring host atoms, whereas Ca-3d orbitals also contribute to the magnetism of Ca-doped systems. Moreover, the doping process enables the emergence of either half-metallic or magnetic semiconductors in the BP monolayer to get prospective d 0 magnetic materials and generate spin current. The results presented herein demonstrate the effectiveness of doping with alkali and alkaline earth metals to obtain magnetized BP monolayers with feature-rich electronic properties, such that the doped systems can be recommended for applications in nano spintronic devices.

Thermodynamic calculations using reverse Monte Carlo: A computational workflow for accelerated construction of phase diagrams for metal hydrides

Metal hydrides are promising candidates for hydrogen storage applications. From a materials discovery perspective, an accurate, efficient computational workflow is urgently required that can rapidly analyze/predict thermodynamic properties of these materials. In this paper, we develop a thermodynamic property estimation/phase diagram construction framework based on the lattice reverse Monte Carlo (RMC) method. We apply the technique to the nickel hydride (NiHx) system by calculating the pressure-composition-temperature (PCT) isotherm and constructing its phase diagram. Formation of nickel hydride entails significant volume expansion, strong interaction between hydrogen and the host atoms, lattice strain, and a phase transition. An attractive feature of our approach is that the entire phase diagram can be accurately constructed in few minutes by considering <10 configurations. In contrast, a popular technique based on grand canonical Monte Carlo would require sampling of several million configurations. The promising results obtained with our computational workflow suggest that the approach can be used in future for wider materials search and discovery.

O- and OH-induced dopant segregation in single atom alloy surfaces: A combined density functional theory and machine learning study

In this study, we identified the significant factors affecting adsorbate-induced segregation in single-atom alloy (SAA) surfaces by performing Density Functional Theory (DFT)-based calculations and machine learning (ML) methods. We used O and OH species, which are key reactants in oxygen reduction reactions (ORR), as test adsorbates. We constructed SAA surfaces using different transition metals (Ag, Au, Co, Cu, Ir, Ni, Pd, Pt, and Rh) and calculated their segregation energies with and without the adsorbates to predict the segregation tendency of the dopant atom. We examined a total of 44 features which comprised of the elemental, energetics, and electronic properties of the SAAs. We employed a two-stage feature selection to reduce the number of features to the most important features for model training. We found that the formation energies, metallic radius difference, the d-band centers of the dopant in the surface and subsurface layer, the difference in surface energy between the host and dopant atoms, and the difference in the total number of d-electrons between the host and dopant atoms influence the segregation energy of the dopant induced by O and OH. Using these selected features, we implemented linear regression (LR), support vector machine regression (SVR), Gaussian process regression (GPR), and extra trees regression (ETR) algorithms to predict the segregation energies in the presence of adsorbates. For both O- and OH-SAA systems, SVR models exhibited the best performance for predicting adsorbate-induced segregation energies. Among the surfaces we considered, we determined Rh-Au(111) as a potential catalyst for ORR based on the calculated adsorption energies of O and OH and segregation energies in the presence of these adsorbates.

First-Principles Dynamics Investigation of Germanium as an Anode Material in Multivalent-Ion Batteries

Germanium, a promising electrode material for high-capacity lithium ion batteries (LIBs) anodes, attracted much attention because of its large capacity and remarkably fast charge/discharge kinetics. Multivalent-ion batteries are of interest as potential alternatives to LIBs because they have a higher energy density and are less prone to safety hazards. In this study, we probed the potential of amorphous Ge anodes for use in multivalent-ion batteries. Although alloying Al and Zn in Ge anodes is thermodynamically unstable, Mg and Ca alloys with Ge form stable compounds, Mg2.3Ge and Ca2.4Ge that exhibit higher capacities than those obtained by alloying Li, Na, or K with Ge, corresponding to 1697 and 1771 mA·h·g–1, respectively. Despite having a slightly lower capacity than Ca–Ge, Mg–Ge shows an approximately 150% smaller volume expansion ratio (231% vs. 389%) and three orders of magnitude higher ion diffusivity (3.0 × 10−8 vs. 1.1 × 10−11 cm2 s−1) than Ca–Ge. Furthermore, ion diffusion in Mg–Ge occurs at a rate comparable to that of monovalent ions, such as Li+, Na+, and K+. The outstanding performance of the Mg–Ge system may originate from the coordination number of the Ge host atoms and the smaller atomic size of Mg. Therefore, Ge anodes could be applied in multivalent-ion batteries using Mg2+ as the carrier ion because its properties can compete with or surpass monovalent ions. Here, we report that the maximum capacity, volume expansion ratio, and ion diffusivities of the alloying electrode materials can be understood using atomic-scale structural properties, such as the host–host and host–ion coordination numbers, as valuable indicators.

Photo-induced conduction behaviour of chemically synthesized copper- doped lead sulphide hexapod

A hexapod-like structure of pure and copper-doped lead sulphide was synthesized by the chemical bath deposition technique. Subsequently, the synthesized structure was analysed through XRD, FESEM, UV–Vis and FTIR spectroscopy. The UV–Vis spectra showed a band gap exceeding 5 eV, a significant variation from the previously reported values. The investigation encompassed the study of photoconductivity switching behaviour of the samples. The results showed that the exposure to UV illumination substantially increases the photo-current. Also, the Ohmic current-voltage characteristic of the pure sample gets transformed to non-linear in the case of the doped sample. This has been attributed to the formation of intermediate states in the forbidden gap as well as the formation of local junctions between host and dopant atom. The optical switching characteristics of samples were also studied and the decay has been well-fitted with second-order exponential decay. This study is a pioneer investigation of photoconductive traits of copper-doped lead sulphide hexapod-like nanostructures.

Computational search for efficient single-photon emitters among the substitutional doping defects in two-dimensional GaSe

Single photon emitters (SPE) in the near-infrared (NIR) spectrum range are critical elements in quantum communication technology. We apply here computational methods to reveal local defects in the GaSe monolayer with properties favorable for such SPEs. Based on an educated guess, we selected twelve defects YX in GaSe, where the Y dopant substitutes the X host atom, X = Ga or Se, and Y = C, Si, Ge, N, P, or As. Our calculations show that two defects, NGa, and PGa, are dynamically unstable. For the remaining defects, we apply the linear response GW method and Bethe-Salpeter equation (BSE) to calculate the electronic structure and optical excitation spectra. Some defects are found to have two sharp peaks (occupied and unoccupied) of the density of the electronic states within the band gap. The NSe-, PSe-, and AsSe-defects have intense sharp an optical excitation peak at energies around 0.8 eV (λ = 1550 nm). Analysis of the formation of the BSE eigenstates associated with these peaks suggests that these excitations can cause a narrow zero-phonon line emission. We thus propose the NSe-, PSe-, and AsSe-defects in the GaSe monolayer as promising SPE in NIR region.

Effects of transition metal elements and O on grain boundary energy and strength of Co by first-principles study

Considering the (210)[001] grain boundary of Co as a model, the influence of transition metals and their coupling with O on the grain boundary energy and strength was investigated by a first-principles-based study. Quantitative characterization was used to explain the transition metal segregation at the grain boundary, and the negative correlation between grain boundary energy and atomic radius was revealed. It has been found that the interaction between the solute and the host atoms at the grain boundary affects the grain boundary strength. Re, W, Os, Cr, Tc, Mo, Ir, Ta, Zr, Ru, Nb, V, Rh, Pt, Pd, and Ni can significantly strengthen the grain boundary, while other transition metals have a weakening effect on the grain boundary. In particular, Cr, Hf, Ta, W, Re, Os, Ir, and Pt can effectively alleviate the weakening of the grain boundary caused by O atoms.

First principles study of hydrogen induced the grain boundaries decohesion in fcc Ag

Hydrogen embrittlement (HE) is a pervasive but harmful physical (chemical) phenomenon, and it has a profound effect on the mechanical properties of metals. Although the study of HE began as early as the near century and a half ago, the essential mechanism of HE still cannot be completely figured out yet. The metallic-H atoms interaction at the atomistic scale is considered the essence of the HE. Especially the interaction of interstitial H and host atoms at grain boundaries is crucial for revealing the HE mechanism. Here, the first principles simulation is applied to study the effect of the trapped H atoms on the grain boundaries (GBs) cleavage behavior. We construct the GBs with different orientations of the face-cantered cubic (fcc) Argentum (Ag) and conduct the ab initio tensile test for all the GBs. The strength of GBs during cleavage, the distortion of GBs structure, and the electronic structure variation induced by trapped H atoms are analyzed. We find the GBs cleavage strength is generally decreased by trapping H atoms at GBs. The decohesion mechanism is the GBs distortion induced by the local electron density variation of the GBs trapping H atoms.