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Design and development of advanced electrocatalysts with high performance and low Pt consumption are crucial for reducing the kinetic energy barrier of the cathode oxygen reduction reaction (ORR) and improving the efficiency of proton exchange membrane fuel cells (PEMFC). In this study, we demonstrate a Pb-modulated PtCo system for efficient ORR, in which the inclusion of Pb in ternary alloys induces dislocation defects due to the significant difference in atomic radius. Dislocation-PtCoPb was confirmed to exhibit significantly higher ORR activity and stability in acidic ORR. In practical PEMFC applications, it outperforms the corresponding commercial Pt/C with a mass activity of 0.58 A ⋅ mg Pt − 1 , making it a promising alternative to state-of-the-art Pt-based catalysts. The combination of experimental results and density functional theory (DFT) calculations offers valuable atomic-level insights into the dislocation structures. Pb with a larger atomic radius is located in the lattice stretching region below the dislocation slip plane, forming a structure similar to a Cottrell atmosphere, which reduces the dislocation energy and puts the system in a lower energy state. The Cottrell atmosphere pins the dislocation structure and stabilizes the ternary alloy. By adjusting the amount of added Pb, a moderate level of dislocation density induces a tuned strain effect, thereby enhancing the electrocatalytic mechanism by optimizing the electronic structure of the alloy surface and the adsorption and desorption of oxygen species. This work provides valuable insights into the design and development of lattice dislocation defect structures to trigger strain effects for improving ORR performance. [ABSTRACT FROM AUTHOR]

University students worldwide are facing increasing mental health challenges. Traditional stress models, like the Job/Study Demand-Resources Model, link stressors directly to strain. Yet, recent studies suggest the influence of strain on stressors may be even stronger. Our research explored these reciprocal dynamics among university students, considering social support and mindfulness as potential moderators. We conducted a two-wave panel study with 264 university students. We ran separate cross-lagged panel structural equation analyses for three key health outcomes—emotional exhaustion, depression, and well-being—each paired with perceived study stressors, specifically workload and work complexity. Findings revealed significant stressor and strain effects, with social support notably moderating the impact of emotional exhaustion on workload. These insights challenge traditional stress theories and underscore the importance of mental health support and effective stress management strategies for students, emphasizing the need for proactive mental health initiatives in academic environments. [ABSTRACT FROM AUTHOR]

During the development of ultrathin two-dimensional (2D) materials, the appearance of ripples has been widely observed. However, the formation mechanisms and their influences are still rarely investigated, especially their contributions to the electronic structures and optical properties. To compensate for the knowledge gap, we have carried out comprehensive theoretical studies on the monolayer WSe2 with a series of ripple structures from 0 to 12 Å in different lattice sizes. The sensitivity of the formation energy, band structures, electronic structures, and optical properties to the ripple structures have been performed systematically for the first time. The formation of ripples in Armchair and Zigzag simultaneously are more energetically favorable, leading to more flexible optimizations of the optoelectronic properties. The improved charge-locking effect and extension of absorption ranges indicate the significant role of ripple structures. The spontaneous formation of ripples is associated with orbital rearrangements and structural distortions. This leads to the unique charge carrier correlate inversion between W-5d and Se-4p orbitals, resulting in the pinning of the Fermi level. This work has supplied significant references to understand ultrathin 2D structures and benefit their future developments and applications in high-performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

The development of economically viable anode catalysts for the alcohol oxidation reaction (AOR) has been a long-standing challenge in direct alcohol fuel cells (DAFCs). A series of Pd–Ag nanoparticles embedded in mesoporous carbon were fabricated in this study using a green approach that did not require the use of a surfactant, which exhibited better catalytic properties for AOR. Experiments and DFT calculations reveal that the d-band center of Pd is influenced by both strain and ligand effects, with the ligand effect predominating. The electrochemical studies demonstrated that the composite-optimized Pd–Ag alloy at a Pd/Ag molar ratio of 1:1 was the highest in terms of ethanol oxidation (EOR) and ethylene glycol oxidation (EGOR) catalytic activity. The mass activities of Pd1Ag1/MC for EOR and EGOR were 7921 mA mg−1 and 11,520 mA mg−1, respectively, which were 3.77 and 5.3 fold greater than Pd/C. The impressive performance of Pd1Ag1/MC catalyst could be attributed to the vital roles of the unique mesoporous structure of carbon sphere with abundant self-doping defect and the boosting effect of Ag (benefit from optimized d-band electronic structure and bi-functional mechanism). The present simple method of synthesizing low-cost, easy-to-use, and high-performance catalysts contributes to the exploration of the large-scale practical applications of direct alkaline alcohol fuel cells. [ABSTRACT FROM AUTHOR]

By means of first-principles calculations, we report the in-plane strain effect on the structural stability, electronic structures, and optical properties of antimonene/germanane van der Waals heterostructure achieved by vertically stacking antimonene and germanene monolayers. The antimonene/germanane heterostructure with type-II band alignment has an indirect band gap of 1.38 eV. The band gap, band alignment, carrier mobility, and optical absorption coefficient of the heterostructure can be tuned by loading in-plane strain. In particular, the in-plane strain can drive multiple indirect–direct–indirect band gap transitions and the band-edge alignment from type-I to type-II. Moreover, the heterostructure exhibits increased hole mobility and ultra-high electron mobility up to 3 × 104 cm2 V−1 s−1 under the tensile strain of 4%. These findings suggest large potential of antimonene/germanane heterostructure for electronic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) have the potential to be a paradigm-shift for rational catalyst discovery but this new type of alloy requires a completely new approach to predict the surface reactivity. In addition to the ligand effect perturbing the surface-adsorbate bond, the random configuration of elements in the surface will also induce local strain effects due to the varying radii of neighboring atoms. Accurate modelling of HEA surface reactivity requires an estimate of this effect: To what degree is the adsorption of intermediates on these lattice distorted atomic environments affected by local strain? In this study, more than 3,500 density functional theory (DFT) calculated adsorption energies of *OH and *O adsorbed on the HEAs IrPdPtRhRu and AgAuCuPdPt are statistically analyzed with respect to the lattice constants of the alloys and the surfaces of each individual binding site. It is found that the inherent distortion of the lattice structure in HEAs releases the local strain effect on the adsorption energy as the atomic environment surrounding the binding atom(s) settles into a relaxed structure. This is even observed to be true for clusters of atoms of which the sizes deviate significantly from the atomic environment in which they are embedded. This elucidates an important aspect of binding site interaction with the neighboring atoms and thus constitutes a step towards a more accurate theoretical model of estimating the reactivity of HEA surfaces. [ABSTRACT FROM AUTHOR]

The present work is based on the computational study of MoS2 monolayer and effect of tensile strain on its atomic level structure. The bandgap for MoS2 monolayer, defected MoS2 monolayer and Silicon-doped monolayer are 1.82 eV (direct bandgap), 0.04 (indirect bandgap) and 1.25 eV (indirect bandgap), respectively. The impact of tensile strain (0-0.7 %) on the bandgap and effective mass of charge carriers of these MoS2 structures has been investigated. The bandgap decrease of 5.76 %, 31.86 % and 6.03 % has been observed in the three structures for biaxial strain while the impact of uniaxial strain is quite low. The impact of higher temperature on the bandgap under biaxial tensile strain has been also analyzed in this paper. These observations are extremely important for 2D material-based research for electronic applications. [ABSTRACT FROM AUTHOR]

A new two-dimensional (2D) carbon allotrope, namely Tetrahexcarbon (TH-carbon) semiconductor monolayer with a direct band gap resides in the visible region of the electromagnetic spectra, has been recently proposed theoretically. Herein, the influences of biaxial strains on the electrical and optical aspects of 2D TH-carbon are computationally investigated. To this end, first-principles calculations based on the properties of the density functional theory were employed. According to our simulations, the electronic and optical properties of 2D TH-carbon are effectively sensitive to the external strain effects. This obtained strain sensitivity suggests that this 2D material could be a promising material for usage in new electronic technologies. [ABSTRACT FROM AUTHOR]

Antiferromagnets (AFMs) with chiral noncollinear spin structure have attracted great attention in recent years. However, the existing research has mainly focused on hexagonal chiral AFMs, such as Mn3Sn, Mn3Ga, Mn3Ge with low crystalline symmetry. Here, we present our systematical study for the face-centered cubic noncollinear antiferromagnetic Mn3Pt. By varying the alloy composition (x), we have successfully fabricated antiferromagnetic Mn1−xPtx epitaxial films on MgO substrates and have observed a crystalline structure transition from L10 MnPt to L12 Mn3Pt. The Mn3Pt exhibits a large anomalous Hall effect, which is in the same order of magnitude as those of ferromagnetic materials. Moreover, a large thickness-evolved strain effect is revealed in Mn3Pt films by X-ray diffraction (XRD) analysis based on the Scherrer method. Our work explores Mn3Pt as a promising candidate for topological antiferromagnetic spintronics. [ABSTRACT FROM AUTHOR]

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In this paper, we present a comprehensive study of the basic electronic properties of two typical two-dimensional materials, monolayer InSe and MoS2 in the presence of various in-plane strains. Our results demonstrate that both materials exhibit similar trends in the variation of band gaps with strain modulations. With the application of strain, a transition between indirect and direct band gap is observed in monolayer InSe. Otherwise, on the application of strains, the band edge of MoS2 shows an excursion from K point and the electron mobility can be enhanced by compressive strain. The electron mobility of InSe can be boosted by about 10% and thus up to 2.24 × 10 3 cm 2 / V s , which approaches one order of magnitude later than that of MoS2. After rebuilding the structure, we introduce illumination to our two-probe system and measure the response. The high responsivity and excellent strain flexibility of InSe rather than MoS2 make it superior as a candidate for the next generation ultrathin electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

The introduction of lattice anisotropy causes Dirac cones to shift in response to the applied strain, leaving a pseudogap at the original Dirac points. Here, a group-theory analysis is combined with first-principles calculations to reveal the movement characteristics of Dirac points and band gaps in various graphynes under rotating uniaxial and shear strains. Graphene, where linear effects dominate, is different from α-, β-, and γ-graphynes, which generate strong nonlinear responses due to their bendable acetylenic linkages. However, the linear components of the electronic response, which are essential in determining material performance such as intrinsic carrier mobility due to electron-phonon coupling, can be readily separated, and are well described by a unified theory. The movement of the Dirac points in α-graphyne is circular under a rotating strain, and the pseudogap opening is isotropic with a magnitude of only 2% that in graphene. In comparison, the movement in β-graphyne is elliptical and the center is displaced from the origin. For γ-graphyne, three branches of gaps change with the applied strains with a sine/cosine dependence on the strain angle. The developed methodology is useful in determining the electronic response to various strains of Dirac materials and two-dimensional semiconductors. [ABSTRACT FROM AUTHOR]

First-principles molecular dynamics simulations have been employed to analyse the proton diffusion in cubic BaZrO $$_3$$ perovskite at 1300 K. A non-linear effect on the proton diffusion coefficient arising from an applied isometric strain up to 2 $$\%$$ of the lattice parameter, and an evident enhancement of proton diffusion under compressive conditions have been observed. The structural and electronic properties of BaZrO $$_3$$ are analysed from Density Functional Theory calculations, and after an analysis of the electronic structure, we provide a possible explanation for an enhanced ionic conductivity of this bulk structure that can be caused by the formation of a preferential path for proton diffusion under compressive strain conditions. By means of Nudged Elastic Band calculations, diffusion barriers were also computed with results supporting our conclusions. [ABSTRACT FROM AUTHOR]

We report on the structure, the chemisorption and the electrocatalytic properties of multilayer (2.2, 3.3 and 5.5 physical monolayers) Pt films deposited on W(111) elaborated by molecular beam epitaxy. The Pt/W(111) surfaces were characterized by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). Pronounced changes of the surface reactivity were noticed as the Pt coverage is decreased. In particular, the affinity for under-potentially deposited hydrogen (H) and hydroxyl (OH) species and the ability to electrooxidize a monolayer of CO were depreciated in agreement with strain and ligand effects. [ABSTRACT FROM AUTHOR]

Controlling magnetism with an electric field is fundamentally important and bears the potential for a wide range of applications. A promising route to circumvent this problem is the appropriately synthesized composite ferroelectric(FE)/ferromagnetic(FM) nano and multilayer structures that may serve as elements in quantitatively new multiferroic devices at room temperature. Two mechanisms, which may underlay the magnetoelectric effect in composite FE/FM junctions, interfacial charge rearrangements and strain effects, are studied as the key ingredients for the magnetoelectric coupling. We demonstrate theoretically a mutual multiferroic response and a complete magnetization switching of a thin FE/FM chain in the presence of a fast oscillating electric field. [ABSTRACT FROM AUTHOR]

An analytical model of the relaxation time for the additional scattering caused by strain in the strained-silicon (Si) layer is proposed and applied to investigate the strain effect on phonon thermal transport in devices using the gray based Boltzmann transport equation (BTE) with relaxation time approximation. With a simple analysis of spring system, it is revealed that the lattice wave with a very long wavelength is mainly generated due to the strain effect. From this fact, the reason of increase in the intravalley phonon in the strained-Si is demonstrated, and the theoretical model for the relaxation time for the strained-Si is established by using the perturbation theory. It is observed that the strain effect is not significant. The reason for this is found that the additional phonon caused by strain scatters preferentially with the wave-phonon mode having the lowest contribution to thermal conduction in the devices. [ABSTRACT FROM AUTHOR]

In this paper, (001)-oriented hexagonal YMnO ( h-YMO) thin films with various nominal strain states were deposited on MgO(100), MgO(111), and YSZ(111) substrates by pulsed laser deposition. The in-plane orientation alignment and substrate-induced epitaxial strain between the h-YMO films and substrates are examined by X-ray diffraction (XRD) θ-2 θ, Φ, and ω scans. The effects of epitaxial strain on the on-site Mn d- d transition energy E( T), and the Néel temperature ( T) in these thin films are investigated by wavelength-tunable ultrafast pump-probe techniques. We find that the changes of E( T) and T depend on the type and magnitude of the epitaxial strain. The possible mechanisms for the observed strain effect on the electronic structure and associated magnetism are discussed. [ABSTRACT FROM AUTHOR]

The two-dimensional Pt submonolayers on Au(111) were used as model catalyst system to study kinetics of hydrogen oxidation reaction (HOR). The morphology of different Pt submonolayers was characterized by ex situ scanning tunneling microscopy combined with statistical image analysis. The HOR kinetics data were analyzed using Levich-Koutecky formalism and presented as a function of the mean size of Pt clusters for each Pt submonolayer. The Pt submonolayers with smaller Pt clusters were found less active for HOR. This trend is well correlated with the continuum elasticity analysis of the average active strain in Pt clusters indicating that smaller clusters have less tensile strain. The density functional theory calculations were found in agreement with our results demonstrating that the size-dependent strain in Pt clusters has significant effect on the energy of the d-band center, i.e., the Pt clusters' activity. [ABSTRACT FROM AUTHOR]

In this report, the electrical properties of both pentacene thin-film and pentacene organic thin-film transistors (OTFTs) under static and dynamic bending were investigated. From the responses to the applied static strain, the piezoresistivity coefficient of pentacene thin-film was determined to be 12.5. Significant changes in the field-effect mobility, μ, and the channel current, which were ascribed to the piezoresistivity of the pentacene channel in OTFTs, were observed while other parameters, such as contact resistance and gate capacitance, appear invariant up to the bending radius of 4.3 mm. Hysteresis in cyclic bending, which was assumed to be caused by local defects of pentacene thin-film, was observed to be independent of bending speed during dynamic bending tests. [ABSTRACT FROM AUTHOR]

A SrTiO thin film was deposited on a MgAlO(100) substrate with a 3.5 % larger lattice constant than that of the SrTiO. The temperature dependence of the dielectric dispersion of the SrTiO thin film was measured by terahertz time-domain spectroscopy, and the dielectric strength and soft-mode frequency showed positive and negative peaks at around 170 K, respectively. In addition, a deviation of the dielectric constant from the theoretical fitting curve in the gigahertz range and an increase in the value of the damping factor were observed below the ferroelectric transition temperature. These phenomena strongly indicate the emergence of ferroelectricity at around 170 K. [ABSTRACT FROM AUTHOR]

Uniaxial tension experiments were performed on monofilament BiPbSrCaCuO (BSCCO)-silver and pure silver tapes. Nearly silver-free BSCCO tapes were also tested to study the influence of the silver phase. In situ measurements of the critical current density (J) vs applied strain provided evidence for the strength and failure behavior of the superconducting oxide core. Final rolling deformation was used as the primary processing variable. BSCCOAg tapes exhibited strain tolerance of up to 0.4% before the superconducting performance began to degrade. The stress-strain response of a near silver-free core was typical of ceramics with brittle failure occurring after an elastic strain of 0.19%. Although not optimized, the yield strength and J improved with greater final rolling deformation. Even greater strain tolerance is postulated by improving the structure and integrity of the oxide core and by increasing the residual compressive stress imposed on the core by the thermal expansion mismatch with the silver sheath. [ABSTRACT FROM AUTHOR]

In this paper, we have studied the effects of temperature, strain and magnetic field on non-extensive entropy of a two-dimensional (2D) quantum dot under spin-orbit interaction. To this end, we have obtained the energy levels and wave functions of the system in the presence of Bychkov-Rashba, Dresselhaus and strain effects by using diagonalization procedure. Then, we have used the Tsallis formalism and calculated the entropy of the system. It is found that the entropy is increased with enhancing the temperature with and without strain. The entropy increases with considering the negative strain. The strain has not strongly effect on the entropy at low temperatures. [ABSTRACT FROM AUTHOR]