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Abstract: Optically active quantum defects play an important role in quantum sensing, computing and communication. The electronic structure and the single-particle energy levels of these quantum defects in the semiconducting host have been used to understand their optoelectronic properties. Optical excitations that are central for their initialization and readout are linked to transitions between occupied and unoccupied single-particle states. It is commonly assumed that only quantum defects introducing levels well within the band gap and far from the band edges are of interest for quantum technologies as they mimic an isolated atom embedded in the host. In this perspective, we contradict this common assumption and show that optically active defects with energy levels close to the band edges can display similar properties. We highlight quantum defects that are excited through transitions to or from a band-like level (bound exciton) such as the T center and Se S i + in silicon. We also present how defects such as the silicon split-vacancy in diamond can involve transitions between localized levels that are above the conduction band or below the valence band. Loosening the commonly assumed requirement on the electronic structure of quantum defects offers opportunities in quantum defects design and discovery especially in smaller band gap hosts such as silicon. We discuss the challenges in terms of operating temperature for photoluminescence or radiative lifetime in this regime. We also highlight how these alternative type of defects bring their own needs in terms of theoretical developments and fundamental understanding. This perspective clarifies the electronic structure requirement for quantum defects and will facilitate the identification and design of new color centers for quantum applications especially driven by first principles computations.

ABSTRACT At present, the metallic interconnects of the solid oxide fuel cell (SOFC) can result in Cr poisoning problem of cathode after long‐term high‐temperature oxidation. Such problem seriously affects the efficiency of battery power generation. In order to optimize the performance of the metallic interconnect, this paper firstly studies the doping effect of rare earth element Y and metal element X (Co, Mn, Ni, Cu) on the diffusion behavior of Cr at the FeCr/Cr2O3 interface by the first principles method. The Cr diffusion pathway and energy barriers under different elemental doping models are calculated by CI‐NEB method. Based upon the theoretical results, the Mn1.8CoY0.2O4 spinel coating is further deposited on the surface of Crofer 22 APU substrate by sol–gel and electrophoretic deposition method to verify the theoretical results. The performance of the coating samples after high‐temperature oxidation are tested and analyzed. The experimental results show that the Mn1.8CoY0.2O4 spinel coating significantly improves the high‐temperature antioxidation, Cr resistance performance, and electrical conductivity of the interconnect, providing a feasible solution for solving the Cr poisoning problem in cathode and accelerating the application of Crofer 22 APU alloy materials in SOFC metallic interconnects. [ABSTRACT FROM AUTHOR]

Electrolytes with fluorinated solvents have been regarded as a promising strategy to stabilize high‐voltage cathodes and the interphase of lithium anode in lithium metal batteries (LMBs). However, the rigorous synthesis approach and high cost have led to a demand for developing cost‐effective solvents with suitable properties for LMBs. Herein, we explored the possibility of using chlorinate solvents as electrolytes using density functional theory (DFT) and classical molecular dynamics (MD) simulation. Taking ether (1,2‐dimethoxyethane [DME], 1,3‐dioxolane [DOL]), carbonate (dimethyl carbonate [DMC], and ethylene carbonate [EC]) as examples, we first compared the energy variation of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) upon Cl and F substitution. In particular, we found that 1,2‐bis(chloromethoxy)ethane (DME‐2Cl‐2) has the lowest HOMO and the highest LUMO level among the chlorinated DME after coordinating with Li+, enabling a potentially wide voltage stability. Further MD simulation reveals that lithium ions in DME‐2Cl‐2 has a weaker solvation coordination with solvents but stronger interaction with anions than DME and 1,2‐bis(Fluoromethoxy)ethane (DME‐2F‐2), which is more beneficial for forming stable anion‐derived solid electrolyte interphase (SEI). Our findings suggest that chlorinated solvents can be used as promising electrolytes for LMBs. [ABSTRACT FROM AUTHOR]

α‐Keggin polyoxometalates (POMs) [XW12O40]n− (X = Al, Si, P, S) are widely used in batteries owing to their remarkable redox activity. However, the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature. Here, first‐principles calculations show that XW12 are core–shell structures composed of a shell and an XO4n− core, both are stabilized by covalent interactions. Interestingly, owing to the presence of a substantial number of electrons in W12O36 shell, the frontier molecular orbitals of XW12 are not only strongly delocalized but also exhibit superatomic properties with high‐angular momentum electrons that do not conform to the Jellium model. Detailed analysis indicates that energetically high lying filled molecular orbitals (MOs) have reached unusually high‐angular momentum characterized by quantum number K or higher, allowing for the accommodation of numerous electrons. This attribute confers strong electron acceptor ability and redox activity to XW12. Moreover, electrons added to XW12 still occupy the K orbitals and will not cause rearrangement of the MOs, thereby maintaining the stability of these structures. Our findings highlight the structure–activity relationship and provide a direction for tailor‐made POMs with specific properties at atomic level. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) GeTe is a popular medium-temperature thermoelectric material, but few studies have focused on strategies for improving its thermoelectric performance. To further investigate the thermoelectric properties of two-dimensional GeTe, different atomic defects are introduced, and the electronic structure and thermoelectric properties are systematically investigated via first-principles calculations and the semiclassical Boltzmann theory. Compared with that of three-dimensional (3D) GeTe, the Seebeck coefficient of 2D GeTe increases from 144 μV K−1 to 560 μV K−1 at 700 K, and the thermal conductivity decreases from 3.3 W m−1 K−1 to 2.3 W m−1 K−1. Thus, the ZT value increases from 0.8 to 1.14. On the basis of these results, the influence of vacancy atomic defects on the thermoelectric performance is investigated. With single-atom defects (SV-Ge and SV-Te), the ZT value increases at constant temperature. However, for double-atom defects in monolayer GeTe, the ZT value increases when DV-585 defects are present but decreases to varying degrees when DV-Ge and DV-Te defects are present. The ZT value of monolayer GeTe with DV-585 defects has an average increase of 0.56 at 300–800 K, which accords well with the experimental results. This study indicates that introducing single-atom vacancy defects somewhat improves the thermoelectric performance of monolayer GeTe, which provides an important point of reference for the development of GeTe in the two-dimensional materials field. [ABSTRACT FROM AUTHOR]

Faced with the challenges of energy depletion and environmental pollution, HER/OER/ORR as the main reactions of the water splitting, fuel cells, and metal-air batteries have garnered a lot of attention. In this paper, the Ga 2 XY (X, Y O, S, Se, Te, X≠Y) structure containing single-atom defect is systematically investigated based on the first principles calculation, and its catalytic and electronic properties are also analyzed in depth. The results demonstrated that the catalytic performance is substantially improved by introducing single-atom defect, the Ga 2 OS, Ga 2 OSe, and Ga 2 SeTe defect structures have more excellent performance. Among all the defect structures, the Ga 2 SeTe structure containing Ga atom defect on the Y-side and adsorbed on Y-side Ga atoms (Ga 2 SeTe- V G a Y -Ga Y) has excellent HER, OER, and ORR performances, the overpotentials is 0.20 eV, 0.30 eV, and 0.51 eV, respectively. The origin of the catalytic activity is also described using crystal orbital Hamilton population (COHP) and charge density calculations. It is shown that the p-orbitals of O and the s-orbitals of Ga undergo significant hybridization, which affects the Ga 2 XY defect structure from the structural level. Our work broadens the research scope in the field of multifunctional catalysis and offers novel approaches to the study of multifunctional catalysts. • Studied the HER/OER/ORR electrocatalytic properties of Ga 2 XY defect structures. • The introduction of single atom enhances the electrocatalytic performance. • Intermediates are more likely to attach to Ga atoms. • The Ga 2 SeTe- V G a Y defect structure showed the best HER/OER/ORR catalytic properties. [ABSTRACT FROM AUTHOR]

Based on the first‐principles calculation of density‐functional theory, the electronic structure and magnetic properties of hexagonal boron phosphide (h‐BP) with doping and applying strain to the transition‐metal (TM = Cr, Mn, Fe, Co, and Ni) elements are investigated. After the TM elements are introduced, the magnetism is induced. The magnetic moments are 3.00, 3.87, 1.00, 1.99, and 1.00 μB, respectively, which mainly contributed by the 3d orbitals of TM elements. In the case of magnetic coupling, Cr–Cr are mainly coupled antiferromagnetically at different distances. In addition, Fe–Fe performs a ferromagnetic state, and Co–Co represents an antiferromagnetic state with the distance of 3.213 Å. After applied strain, Co doped of the system shows the characteristics of semimetals under the application of 4% strain. It can be added that for h‐BP systems, doping Co and Mn increases its conductivity, which is beneficial to the study of spintronic materials. [ABSTRACT FROM AUTHOR]

In this work, the density functional theory is used to investigate the structural, mechanical, electronic, dynamic, thermodynamic, optical and hydrogen storage properties of XLiH 3 (X = K, Rb) for the first time. Both KLiH 3 and RbLiH 3 materials exhibit dynamic, mechanical and thermodynamic stability. The lattice parameters of KLiH 3 and RbLiH 3 are 3.908 and 4.070 Å, respectively. The investigation of Cauchy pressure, Poisson's ratio and B/G ratio shows that KLiH 3 and RbLiH 3 are brittle materials. Moreover, the electronic properties of XLiH 3 hydrides demonstrate that KLiH 3 and RbLiH 3 show metallic nature. Optical properties of these compounds are studied and reveal that they have very high refractive indexes and dielectric functions. The thermodynamic properties, including heat capacity, entropy, enthalpy, and free energy of XLiH 3 , are investigated as well. The hydrogen storage capacities of KLiH 3 and RbLiH 3 are 5.805 and 3.071 wt%, respectively, confirming that KLiH 3 has a high hydrogen storage capacity and is more suitable as a hydrogen storage material. Our study opens up a new-pathway for designing novel hydrogen storage materials. • XLiH 3 (X = K, Rb) perovskite hydrides have been investigated using first-principles. • XLiH 3 (X = K, Rb) exhibit thermodynamic, mechanical, and dynamical stability. • The hydrogen storage capacity of XLiH 3 is 5.805 wt% and 3.071 wt%, respectively. • Our studies propose that KLiH 3 is a more suitable hydrogen storage material. [ABSTRACT FROM AUTHOR]

Heterojunction is widely acknowledged as a potent strategy as an effective means for achieving quality electronic, optical adsorption, and photocatalytic water-splitting properties. Strain also can regulate these properties effectively. In this study, we have fabricated and studied a heterojunction comprised SiC and WS 2. Utilizing a first-principles method, we systematically investigated the SiC/WS 2 heterojunction's structure, stability, electronic, and optical properties, as well as its photocatalytic water splitting characteristics under strain engineering. Our calculations reveal that the SiC/WS 2 heterojunction is a type-II heterostructure with two stable structures, which exhibits a direct bandgap and well performance in the visible light region, facilitating efficient separation of photogenerated electron-hole pairs. We have explored and discussed the impacts of biaxial strain on the various properties. The bandgaps of System-A and B are 1.778 eV and 1.820 eV, respectively, without strain. Under strain from −6% to 10%, they initially rise, peak at 1.858 eV and 1.899 eV respectively at −2% strain, then decline. Without strain, effective mass m h /m e for both structures are 1.642 and 1.673. Under positive strain, they increase, decrease, then increase again, peaking at 6% with 2.116 and 2.260. At −2% strain, values drop to 0.901 and 0.910 for A and B, respectively. Our calculations also demonstrate that the SiC/WS 2 heterostructure qualifies as a promising photocatalytic material, fulfilling the criteria for water splitting under strain conditions of −4%, −2%, and 0%. And the heterojunction with System-B under −4% strain has the optimal performance in photocatalytic water splitting. At a strain of −4%, System-B achieves the maximum η′ STH of 16.91%. In conclusion, our study not only offers fundamental insights into the utilization of SiC/WS 2 heterojunctions for photocatalytic water splitting, but also provides the foundational design principles of heterojunctions. • SiC/WS 2 heterojunction is a type-II heterostructure with a direct bandgap. • The heterojunction has well performance in the visible light region. • The built-in electric field facilitates efficient separation of photogenerated electron-hole pairs. • Strain can effectively modulate the electronic and optical properties of the heterojunction. • Structure-Ⅱ under −4% strain has the best performance in photocatalytic water splitting. [ABSTRACT FROM AUTHOR]

The single-layer MoS2 is a highly sought-after semiconductor material in the field of photoelectric performance due to its exceptional electron mobility and narrow bandgap. However, its photocatalytic efficiency is hindered by the rapid recombination rate of internal photogenerated electron–hole pairs. Currently, the construction of heterojunctions has been demonstrated to effectively mitigate the recombination rate of photogenerated electron–hole pairs. Therefore, this paper employs the first principles method to calculate and analyze the four heterojunctions formed by MoS2/WSe2, MoS2/MoSe2, MoS2/AlN, and MoS2/ZnO. The study demonstrates that the four heterojunctions exhibit structural stability. The construction of heterojunctions, as compared to a monolayer MoS2, leads to a reduction in the band gap, thereby lowering the electron transition barrier and enhancing the light absorption capacity of the materials. The four systems exhibit II-type heterojunction. Therefore, the construction of heterojunctions can effectively enhance the optical properties of these systems. By forming heterojunctions MoS2/WSe2 and MoS2/MoSe2, the absorption coefficient in the visible light region is significantly increased, resulting in a greater ability to respond to light compared to that of MoS2/ZnO and MoS2/AlN. Consequently, MoS2-based heterojunctions incorporating chalcogenide components WSe2 and MoSe2, respectively, exhibit superior catalytic activity compared to MoS2 heterojunctions incorporating non-chalcogenide components ZnO and AlN, respectively. The absorption spectrum analysis reveals that MoS2/MoSe2 exhibits the highest light responsivity among all investigated systems, indicating its superior photoelectric performance. [ABSTRACT FROM AUTHOR]

Two-dimensional semiconductor materials with natural bandgap are expected to make up for the zero bandgap defect of graphene and break the bottleneck of its application in fields such as field effect transistors,switching devices,logic circuits. Compared with layered semiconductor materials,non-layered semiconductor materials are usually bound by strong ionic/covalent bonds and are isotropic,so it is a challenge to obtain their two-dimensional structures. In this paper,two-dimensional anisotropic growth of nonlayered CdSe on mica substrate was achieved by chemical vapor deposition. The microstructure,crystalline structure and optical properties of two-dimensional CdSe were characterized in detail. The results show that the sample has a significant photoluminescence ( PL) effect,indicating that the thickness thinning to nanometer level does not destroy the direct bandgap property of CdSe. In addition,with the decrease of thickness,PL peaks of the sample are gradually blue-shifted. In order to further explain this phenomenon,the energy band structures of CdSe with different thickness were studied using the first-principles caculation based on density functional theory. The results show that they all have direct bandgap,and the bandgap increases with the decreasing thickness,which is consistent with the experimental phenomenon. Therefore,the effective control of the bandgap can be achieved by adjusting the thickness of two-dimensional CdSe through the growth parameters,which has guiding significance for the performance improvement of related optoelectronic devices. [ABSTRACT FROM AUTHOR]

The structural stability,mechanical and electronic properties of three types of Re-doped Os B4 were studied by the Vienna Ab initio Simulation Package (VASP) .The Os element in the P42/nmc phase Os B4 was substituted by the Re element,and the structural model of the Os1-xRexB4 (x=0,0.0625,0.125,0.25) solid solution systems were constructed.The results show that the lattice constant and volume of Os1-xRexB4increase slightly with the increase of Re content,and the structural distortion occurs when x is higher than 0.25;The structures and thermodynamics of the Os1-xRexB4 (x=0,0.0625,0.125) are stable;The density of states mainly comes from the 5d electrons of Os and the 2s and 2p electrons of B,and the 5d orbital electrons of Re atoms also contribute to the valence band and conduction band,with the increase of its content,the peak provided also increases;the strong covalent interaction of B-B and B-Os bonds are the main reason for their higher bulk moduli and shear moduli.As the concentration of Re element increases,the conductivity and ductility of the structure increase to a certain extent. [ABSTRACT FROM AUTHOR]

Al Si7-SiC composite was prepared by semi-solid stirring casting,and its near-net shape forming was achieved by vacuum die casting.The influence of eutectic Si segregation on the interface strength of SiC-Al composite was studied by the first principles calculation method.The results shown that a mass of eutectic Si segregation was found in the matrix of the prepared Al Si7-SiC composites and three typical interfaces were formed:mixed up with a few eutectic Si,a half trapped in eutectic Si and completely trapped in eutectic Si.The calculation results shown that the Si/SiC interface with C-terminated and Si-terminated,the topSi~1coordination mode has the largest adhesion work after relaxation.The interface bonding strength of the Si/Si C interface is greater than that of the Al/Si C interface.Compared with the Al/Si C interface,the Si/SiC interface had a better stability of interface structure attributed to the strong covalent bond formed at the Si/SiC interface and the segregated Si phase improved the interfacial charge density. [ABSTRACT FROM AUTHOR]

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Using first-principles density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations, we performed this study on the phase stability, the intrinsic redox stability, and the Li+ conductivity of Li10GexMo1−xP2S12 (x = 0~1) superionic conductors. Molybdenum (Mo) is expected to replace expensive germanium (Ge) to lower tmaterial costs, reduce sensitivity to ambient water and oxygen, and achieve acceptable Li+ conductivity. The ab initio first principle molecular dynamics simulations show that room-temperature Li+ conductivity is 1.12 mS·cm−1 for the Li10Ge0.75Mo0.25P2S12 compound, which is comparable to the theoretical value of 6.81 mS·cm−1 and the experimental measured one of 12 mS·cm−1 of the Li10GeP2S12 (LGPS) structure. For Li10GexMo1−xP2S12 (x = 0, 0.25, 0.5 and 1) compounds, the density of states and the projection fractional wave state density were calculated. It was found that when Ge atoms were partially replaced by Mo atoms, the band gap remained unchanged at 2.5 eV, but deep level defects appeared in Mo-substituted compounds. Fortunately, this deep level defect is difficult to ionize at room temperature, so it has no effect on the electronic conductivity of Mo substitute compounds, making Mo substitution a suitable solution for electrolyte materials. The projection fractional wave state density calculation shows that the covalent bond between Mo and S is stronger than that between Ge and S, which reduces the sensitivity of Mo-substituted compounds to water and oxygen contents in the air. In addition, the partial state density coincidence curve between Li and S elements disappears in the 25% Mo-substituted compound with energies of 4–5 eV, indicating that the Li2S by-product is decreased. [ABSTRACT FROM AUTHOR]

Rechargeable batteries have been regarded as a truly transformative technology, providing energy storage for portable electronics, power tools, and even electric vehicles. Unfortunately, the practical applications of new battery systems are postponed by some inevitable technical bottlenecks. Sometimes the technical know‐how gained from the current state‐of‐the‐art lithium‐based batteries is untransferable. Therefore, with the continuous development of chemistry, materials and physics, computational materials science has gradually become crucial in supporting the field of rechargeable batteries technically. In this review, brief overviews of computational methods are first presented for the research of battery materials. The study then summarizes the recent advances of computational techniques in assisting experimental analyses, elucidating reaction mechanisms, and exploring new materials. Finally, the challenges and perspectives for future computational research are prospected. This review is anticipated to stimulate design inspiration of novel materials and structures with the assistance of theoretical simulations toward advanced energy storage systems. [ABSTRACT FROM AUTHOR]

In this study, the effect of alkaline-earth metal element doping on the photoelectric properties of intrinsic MoSe2 is systematically investigated based on the first-principles approach, and it is believed that the findings of this work will give some theoretical guidance for future research on MoSe2 doping modification. The results show that all the doping systems exhibit good stability, and Be atom doping has the lowest formation energy value, making the doping easier to produce. The doping of alkaline-earth metal elements resulted in some lattice distortion of MoSe2. Intrinsic MoSe2 is a semiconductor with a direct bandgap of 1.498 eV, and the doping of alkaline-earth metal elements causes the bandgap value to decrease in each system, and the bandgap is the smallest when Be is doped. All doped systems exhibit P-type conducting properties. Compared with the intrinsic MoSe2, all doped systems have their conduction band fraction moved to the low-energy direction overall, and new density of states peaks appear near the Fermi energy level. These state density peaks mainly originate from the results contributed by the s-orbitals of each doping system Mo-4d, Se-4p, and each dopant atom. The analysis of the work function reveals that the work function of each doped system is smaller than the intrinsic MoSe2, then the energy required for the occurrence of electron leaps is reduced, which improves the electron mobility of the doped system. The Mulliken Population analysis shows that stable chemical bonds are formed between the doped alkaline-earth metal elements and the surrounding Se atoms. The examination of the optical characteristics demonstrated that, in comparison to the intrinsic MoSe2, all doped systems' greatest dielectric absorption peaks were attenuated and moved toward the low-energy region; the doping of alkaline-earth metal elements broadened the light absorption edge of the intrinsic MoSe2. The absorption peaks of each doping system are shifted toward the low-energy region with the red-shift phenomenon, and the light absorption is good in the ultraviolet region. [ABSTRACT FROM AUTHOR]

Doping engineering is crucial for both fundamental science and emerging applications. While transition metal (TM) dopants exhibit considerable advantages in the tuning of magnetism and conductivity in bulk Ga2O3, investigations on TM-doped two-dimensional (2D) Ga2O3 are scarce, both theoretically and experimentally. In this study, the detailed variations in impurity levels within 3d TM-doped 2D Ga2O3 systems have been explored via first-principles calculations using the generalized gradient approximation (GGA) +U method. Our results show that the Co impurity tends to incorporate on the tetrahedral GaII site, while the other dopants favor square pyramidal GaI sites in 2D Ga2O3. Moreover, Sc3+, Ti4+, V4+, Cr3+, Mn3+, Fe3+, Co3+, Ni3+, Cu2+, and Zn2+ are the energetically favorable charge states. Importantly, a transition from n-type to p-type conductivity occurs at the threshold Cu element as determined by the defect formation energies and partial density of states (PDOS), which can be ascribed to the shift from electron doping to hole doping with respect to the increase in the atomic number in the 3d TM group. Moreover, the spin configurations in the presence of the square pyramidal and tetrahedral coordinated crystal field effects are investigated in detail, and a transition from high-spin to low-spin arrangement is observed. As the atomic number of the 3d TM dopant increases, the percentage contribution of O ions to the total magnetic moment significantly increases due to the electronegativity effect. Additionally, the formed 3d bands for most TM dopants are located near the Fermi level, which can be of significant benefit to the transformation of the absorbing region from ultraviolet to visible/infrared light. Our results provide theoretical guidance for designing 2D Ga2O3 towards optoelectronic and spintronic applications. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) Janus materials are a fascinating class of materials resulting from their unique electronic and magnetic properties induced by mirror symmetry breaking. However, 2D Janus materials with intrinsic magnetism remain rather rare, casting a mysterious veil over magnetism. In this work, the electronic and magnetic properties of Janus Mn2GeX (X = As, Sb) monolayers using the first‐principles calculations are investigated. The results demonstrate that these Janus materials exhibit excellent mechanical and dynamic stability, indicating their potential for future applications in nanoscale spintronic devices. Interestingly, the Janus Mn2GeAs$\left(\text{Mn}\right)_{2} \text{GeAs}$ and Mn2GeSb$\left(\text{Mn}\right)_{2} \text{GeSb}$ monolayers possess exciting half‐metallic character with wide half‐metallic gaps of 0.29 and 0.18 eV, and spin gaps of 1.68 and 1.62 eV, respectively. Their calculated ground state exhibits a strong preference for ferromagnetic ordering, with a Curie temperature (Tc$T_{c}$) of 630 and 590 K, respectively. Additionally, the ferromagnetism of Janus Mn2GeX (X = As, Sb) monolayers is robust against biaxial strain ranging from −6% to 6%. Under 6% tensile strain, the calculated Tc$T_{c}$ of the Mn2GeSb$\left(\text{Mn}\right)_{2} \text{GeSb}$ monolayer is 639 K, which represents a 9% increase compared to the Tc$T_{c}$ observed in the unstrained condition. All these intriguing electronic and magnetic properties make the Janus Mn2GeX (X = As, Sb) monolayers an appealing candidate for applications in nanoscale spintronic devices. [ABSTRACT FROM AUTHOR]

2D magnetic materials with high spin polarization and Curie temperature are highly desirable for ultrathin spintronic devices. This study utilizes first‐principles methods to systematically investigate 225 O adsorption configurations, demonstrating that Cr2COx MXene consistently maintains a long‐range‐ordered ferromagnetic arrangement with high spin polarization, irrespective of the O adsorption configuration. Most configurations also display Curie temperature (TC) exceeding room temperature, with the possibility of further enhancement by reducing O coverage. Machine learning models are developed to accurately predict O adsorption configurations, exchange interaction energies, and TC. A novel approach of stripping F and OH groups to create Cr2COx on Cr‐based MXene surfaces is proposed to address the difficulty in achieving long‐range‐ordered magnetic structures by manipulating surface adsorbates in MXene. This approach enhances the ability to control the magnetic properties of MXenes and paves the way for their application in ultrathin spintronic devices. [ABSTRACT FROM AUTHOR]

BaZrO 3 -based oxides have attracted attention due to their intrinsic properties that allow protons to traverse. To accelerate proton conduction, a novel BaZr 0.5 Gd 0.25 Y 0.25 O 3 (BZGY) material is proposed as the electrolyte of proton ceramic fuel cells (PCFCs). The electronic structure, synergistic effect and proton transport mechanism of Gd and Y co-doped BaZrO 3 are theoretically studied. Y-doping and Gd-doping promote the formation of oxygen vacancies and the entry of H 2 O molecules into the structure and binding to oxygen vacancies, respectively. The co-doping of Y and Gd promotes the hydration process and increases the proton concentration. The binding of Gd or Y to the oxygen vacancy around the acceptor inhibits proton trapping. BZGY shows rapid and long-distance transport of protons. BZGY has obtained high proton concentrations and mobility, which fully support its potential application in next-generation PCFCs. The synergistic effects of Gd and Y co-doped BaZrO 3 provide important theoretical significance for the study of proton electrolytes. [ABSTRACT FROM AUTHOR]

In this paper, the structure and electronic properties of InP/PtS 2 heterojunction as well as the photocatalytic and solar hydrogen production efficiency are studied by first principles. Studies have shown that InP/PtS 2 heterojunction is type II band alignment, typical Z heterostructure, has strong light absorption coefficient in the absorption spectrumand, InP/PtS 2 heterojunction with an indirect bandgap of 1.97 eV，the band edge positions that meet the energy band prerequisites for water splitting across different pH levels，The band edge positions and light absorption capabilities have been modified through biaxial strain, with tensile strain enhancing the absorption capacity within the visible light spectrum ranging from 450 to 800 nm(nm). The InP/PtS 2 heterojunction achieves a solar-to-hydrogen conversion efficiency (ηSTH) of 32.5%, which is higher than that of most heterojunctions. The InP/PtS 2 heterojunction is anticipated to emerge as a promising contender for the next generation of photocatalysts. InP/PtS 2 heterojunction is a typical direct Z-scheme heterojunction, which can change its electronic and optical properties under strain, and may contribute to the fields of water splitting. The solar-to-hydrogen efficiency of the InP/PtS2 heterostructure can reached 32.5%. The absorption coefficient in the visible range is enhanced by the application of strain. [Display omitted] • Compared with InP monolayer and PtS 2 monolayer, InP/PtS 2 heterojunctions have better visible light absorption efficiency. • The InP/PtS 2 heterojunction achieves a solar-to-hydrogen conversion efficiency (ηSTH) of 32.5%, which is higher than that of most heterojunctions. [ABSTRACT FROM AUTHOR]

Black phosphorene is a kind of two-dimensional layered material with special structure and excellent physical properties. It is a kind of middle temperature thermoelectric material with application prospect. In this paper, the advantages and disadvantages of the two methods are discussed by summarizing and comparing the experimental research and simulation calculation methods of the thermoelectric properties of black phosphorene. The characteristics and unique anisotropy of the thermoelectric transport performance of black phosphorene were studied, and the influence of different regulation methods on the thermoelectric transport performance of black phosphorene was analyzed. This paper can provide reference for the research methods of related thermoelectric materials. [ABSTRACT FROM AUTHOR]

Ferroelectric charged domain walls offer a revolutionary path for next-generation ferroelectric devices due to their exceptional conductivity within an otherwise insulating matrix. However, quantitative understanding of this "giant conductivity" has remained elusive due to the lack of robust models describing carrier behavior within CDWs. The current paper bridges this critical knowledge gap by employing a first-principles approach that incorporates Boltzmann transport theory and the relaxation time approximation. This strategy enables the calculation of carrier concentration, mobility, and conductivity for both head-to-head and tail-to-tail domain wall configurations within a stabilized periodic structure. The comprehensive transport analysis given here reveals that the accumulation of charge carriers, particularly their concentration, is the dominant factor governing domain wall conductance. Interestingly, observed conductance differences between head-to-head and tail-to-tail walls primarily arise from variations in carrier mobility. Additionally, this study demonstrates a significantly reduced domain wall width compared to previous reports. This miniaturization is attributed to the presence of compressive strain, which lowers the energy barrier for electron–hole pair generation. Furthermore, the findings here suggest that reducing the band gap presents a viable strategy for stabilizing charged domain walls. These results pave the way for the optimization and development of domain wall devices across a spectrum of ferroelectric materials. [ABSTRACT FROM AUTHOR]

It is very important to obtain a new FE-PV material with a narrow bandgap and a large ferroelectric polarization to induce the development of FE-PV materials. On the basis of InP, a high visible light absorption material, we calculate the wurtzite structure In1 − xScxP in this work. Interestingly, it was found that a new ferroelectric phase t-In0.5Sc0.5P (a trigonal structure with space groups P3m1), which is the transition phase from the ferroelectric phase w-In0.5Sc0.5P to the paraelectric phase In0.5Sc0.5P (p-In0.5Sc0.5P), has a lower energy than w-In0.5Sc0.5P. The polarization switching barrier of t-In0.5Sc0.5P decreased remarkably from 0.95 eV of w-InP to 0.093 eV due to the introduction of Sc. The ferroelectric polarization of t-In0.5Sc0.5P is 21.2 µC/cm2. t-In0.5Sc0.5P has excellent visible light absorption properties compared to those of w-InP and Si in the long wavelength range. This work shows that the III-V doping groups are potential FE-PV materials. [ABSTRACT FROM AUTHOR]

Magnetizing the surface states of topological insulators without damaging their topological features is a crucial step for realizing the quantum anomalous Hall (QAH) effect and remains a challenging task. The TI–ferromagnetic material interface system was constructed and studied by the density functional theory (DFT). A two-dimensional magnetic semiconductor CrWI6 has been proven to effectively magnetize topological surface states (TSSs) via the magnetic proximity effect. The non-trivial phase was identified in the Bi2Se3 (BS) films with six quantum layers (QL) within the CrWI6/BS/CrWI6 heterostructure. BS thin films exhibit the generation of spin splitting near the TSSs, and a band gap of approximately 2.9 meV is observed at the Γ in the Brillouin zone; by adjusting the interface distance of the heterostructure, we increased the non-trivial band gap to 7.9 meV, indicating that applying external pressure is conducive to realizing the QAH effect. Furthermore, the topological non-triviality of CrWI6/6QL-BS/CrWI6 is confirmed by the nonzero Chern number. This study furnishes a valuable guideline for the implementation of the QAH effect at elevated temperatures within heterostructures comprising two-dimensional (2D) magnetic monolayers (MLs) and topological insulators. [ABSTRACT FROM AUTHOR]

Onion-like fullerenes (OLFs) have spherical and tunable shell structures that make them perfect solid lubricants, but their molecular mechanical properties are largely unknown as they are extremely difficult to measure. In this computational study, double-shelled OLFs C60@C180, C80@C180, C60@C240 and C80@C240 are subject to uniaxial elastic strains to obtain their mechanical response. Compressive and tensile elastic moduli are calculated using density functional theory with van der Waals correction. We found that the tensile elastic moduli of the single- and double-shelled fullerenes are always larger than the compressive ones by about 50% to 100%. Inserting C80 into C180 causes an increase in compressive elastic modulus from 96.8 GPa to 178.6 GPa, while inserting C60 into C240 cause much smaller increases. The key factor that determines the stiffening effects is the relative sizes of the inner and outer shells. [ABSTRACT FROM AUTHOR]

Zr has been widely used in high-quality steel due to its strong deoxidizing capacity and ability of improve performance of steel. ZrO2–Al2O3 inclusions with core-shell structure were observed in this study. The structure, electronic properties, and energy changes of ZrO2 and ZrO2–Al2O3 systems were studied based on first principles calculation. It indicates that ZrO2 can be used as the heterogeneous nucleation core of Al2O3. Al atoms were preferentially adsorbed on the bridge site of ZrO2 (001) and then form the ZrO2–Al2O3 interface. The template effect of ZrO2 was nine adsorption atomic layers, among which layers 1–5 was a coherent epitaxial layer, layers 5–9 was the transition layer, and the atomic ratio was 3:2. The growth mechanism of Al2O3 on ZrO2 surface was discussed. The results help understand the formation of inclusion at atomic scale and find ways to control the characteristics of inclusion in steel with Zr treatment. [ABSTRACT FROM AUTHOR]

The prototype misfit layer compound (SnS)1.17NbS2 consists alternatingly of a metallic triatomic NbS2 layer, in which Nb atoms are sandwiched by S atoms, and an insulating SnS double layer featuring a NaCl-type structure. Here we investigate the effect of lattice misfit on the stability and chemical bonding in the misfit layer compound using a first-principles density functional theory approach. The calculations show that for the (SnS)1+xNbS2 approximants, the most stable one has x = 0.167, close to the experimental observations. Charge analysis finds a moderate charge transfer from SnS to NbS2. Sn or S vacancies in the SnS part affect the electronic properties and interlayer interactions. The obtained information here helps in understanding the mechanism of formation and stability of misfit layer compounds and ferecrystals and further contributes to the design of novel multilayer compounds and emerging van der Waals heterostructures. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable energy, magnesium hydride (MgH2) stands out as a promising candidate for hydrogen storage due to its high capacity. Nevertheless, its high thermodynamic stability necessitates elevated operating temperatures, thereby hindering practical applications. To mitigate this limitation, our study employs a defect engineering approach by introducing a mono-vacancy to decrease its thermodynamic stability. Utilizing first-principles density functional theory calculations, we investigate the influence of a mono-vacancy on the structural and electronic properties of MgH2 crystal. Introducing the defect results in a 0.57 % contraction of the a / b lattice parameters and a 1.03 % expansion along the c-axis, causing lattice distortion. Electronically, the band gap narrows by 0.67 eV, indicating an increase in metallic character. We observe a distinct vacancy-affected zone, characterized by substantial alterations in electron density within a 26.505 Å3 volume and modifications to the potential energy distribution encompassing a 19.514 Å3 volume. The mono-vacancy enhances the polarity of the Mg-H bonds and maximally decreases the bond energy by 0.065 eV. A localized high-energy region of 0.354 eV emerges, functioning as an energy barrier to atomic diffusion. This energy barrier is encompassed by low-energy pathways, potentially facilitating H atom migration within the MgH2 crystal. [ABSTRACT FROM AUTHOR]

Uranium-zirconium alloy is an important nuclear fuel in Integral Fast Reactor, which is of great significance to study its basic physical properties at high temperature by using advanced calculation methods. This work used deep potential molecular dynamics method, which combines the high accuracy of the first principles with the high efficiency of the classical molecular dynamics, to perform an evaluation of the static and thermophysical properties of body-centered cubic phase zirconium, uranium, and uranium-zirconium alloy. Firstly, the deep potential(DP) models of body-centered cubic zirconium(Zr-BCC), body-centered cubic uranium(U-BCC), and body-centered cubic uranium-zirconium alloy(U-Zr（BCC）) were trained by using deep neural network machine learning. Secondly, the DP models were used to predict equilibrium state equation, lattice constant, elastic properties, and phonon spectrum of the three systems, and the predicted results can reach the accuracy of the first principles. Then, the variation of heat capacity and density at constant pressure of Zr-BCC, U-BCC, and U-Zr（BCC） with temperature were predicted by using DP models, and the results are in good agreement with the experimental values. The research results show that the machine learning method provides an important path for successfully exploring more complex nuclear fuel properties.

This article adopts the first principles calculation method to study the defects of La doped ZnO, and analyzes the different occupying defects of La in ZnO: the formation energy, energy band, and density of states of substitution and interstitial defects. It has been proven that during the growth process of La doped ZnO, the possibility of La atoms replacing of Zn atoms to form substitution site defects is greater than La atoms entering the interstitial site to form interstitial site defects. When forming substitution site defects, choosing an oxygen rich growth environment is better than the zinc rich growth environment. Substitution site defects help improve the conductivity of ZnO and improve its performance. The research results of this article can provide a certain theoretical reference for the experimental phenomena and application directions of La doped ZnO. [ABSTRACT FROM AUTHOR]

The geometric structure, electronic properties and interaction with carbon monoxide (CO) of platinum-modified (5,5) aluminum nitride nanotubes were studied by first-principles density functional theory. The results show that the energy of platinum atom adsorbed on the top site of nitrogen atom on the surface of aluminum nitride nanotubes is the lowest. Four CO molecules can be adsorbed near the platinum atom, and the average adsorption energy is between 1.189−2.940 eV. The modification of platinum atoms effectively improves the adsorption capacity of aluminum nitride nanotubes for CO molecules. This study provides theoretical guidance for the experimental development of CO gas sensors with better performance. [ABSTRACT FROM AUTHOR]

CO, SO2, H2S are typical toxic gases gushing out of coal and surrounding rock or produced during production in mines. In the paper, first principles and density functional theory were used to study the adsorption characteristics of rare earth element Sc-doped ZnO on single gas molecules (CO, SO2, H2S). Through the analysis of the Mulliken, band structure, DOS and DCD of each system, the results show that: Sc-ZnO(001)-Zn position doping system has the best stability, the adsorption energy of Sc-ZnO on individual CO, SO2 and H2S molecules was -0.140 eV, -1.885 eV and -0.093 eV, respectively, of which the adsorption of SO2molecules was chemical adsorption and the rest was physical adsorption. The feasibility of Sc-ZnO as a semiconductor gas sensor to detect three toxic gases was determined, especially for SO2 gas, which provided theoretical guidance for Sc-ZnO as a gas sensing material to detect toxic gas in mines. [ABSTRACT FROM AUTHOR]

Wearable sensors with excellent comfort, flexibility and fast response are widely applied in human-machine interactions, artificial skin, motion detection and healthcare monitoring. However, preparation processes of the most of current piezoelectric sensors are relatively expensive and complicate, limiting their mass productions in the applications. This work demonstrates the superior piezoelectric performance and stability of ZnO/AlN flexible thin films prepared by magnetron sputtering for broad-range human motions detection, and first-principles calculation are applied to reveal the complicate piezoelectric effect of the hybrid system. The ZnO/AlN hybrid thin films sensor exhibits superior piezoelectric performance and excellent reliability, with presenting high outputs voltage (3.63 V), high degree of response speed (42.33 ms), water stability and robust performance upon 10000 cycles. First-principles calculations reveal that formation of the ZnO/AlN interface facilitates charge transport and improves efficiency of carrier transport, and results in reduced in band gap and enhanced electrical conductivity. By applying the sensors in human health monitoring, the underlying behaviors can be determined by output voltage of the sensor in real-time. This work offers a sensitive, simple structured and robust solution for human motion detection. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper discusses three points inspired by Skraaning and Jamieson's perspective on automation failure: (a) the limitations of the automation failure concept with expanding system boundaries; (b) parallels between the failure to grasp automation failure and the failure to grasp trust in automation; (c) benefits of taking a pluralistic approach to definitions in sociotechnical systems science. While a taxonomy of automation-involved failures may not directly improve our understanding of how to prevent those failures, it could be instrumental for identifying hazards during test and evaluation of operational systems. [ABSTRACT FROM AUTHOR]

The occurrence of hydrogen embrittlement often leads to significant fracturing in materials. Thus, a comprehensive understanding of the interactions of hydrogen and its effects on material properties is essential. In this study, first‐principle calculations based on density functional theory are conducted to investigate the adsorption and diffusion characteristics of hydrogen at the Ni/Ni3Al(γ/γ') interface of a Ni‐based single‐crystal superalloy. The results show that hydrogen can stably adsorb onto the γ/γ′ interface, nearby octahedral interstitial sites, and tetrahedral interstitial sites in the γ‐phase. Analysis of the density of states and charge density confirms that the hydrogen atoms formed covalent bonds and ionic bonds with nearby Al atoms. A transition state structure search based on linear synchronous transit (LST) and quadratic synchronous transit (QST) models is utilized to calculate the diffusion paths and energy barriers of the hydrogen atoms between the stable adsorption sites near the interface. In addition, the permeation characteristics of hydrogen atoms at the interface are analyzed. Furthermore, it is confirmed that hydrogen atoms entering the matrix from the interface preferentially occupy the positions of the regular octahedral interstitial sites, diffuse towards adjacent regular 6Ni octahedral interstitial sites through the inclined octahedral interstitial sites between the atomic layers, and converge at the interface. [ABSTRACT FROM AUTHOR]

Ferroelectric charged domain walls offer a revolutionary path for next-generation ferroelectric devices due to their exceptional conductivity within an otherwise insulating matrix. However, quantitative understanding of this “giant conductivity” has remained elusive due to the lack of robust models describing carrier behavior within CDWs. The current paper bridges this critical knowledge gap by employing a first-principles approach that incorporates Boltzmann transport theory and the relaxation time approximation. This strategy enables the calculation of carrier concentration, mobility, and conductivity for both head-to-head and tail-to-tail domain wall configurations within a stabilized periodic structure. The comprehensive transport analysis given here reveals that the accumulation of charge carriers, particularly their concentration, is the dominant factor governing domain wall conductance. Interestingly, observed conductance differences between head-to-head and tail-to-tail walls primarily arise from variations in carrier mobility. Additionally, this study demonstrates a significantly reduced domain wall width compared to previous reports. This miniaturization is attributed to the presence of compressive strain, which lowers the energy barrier for electron–hole pair generation. Furthermore, the findings here suggest that reducing the band gap presents a viable strategy for stabilizing charged domain walls. These results pave the way for the optimization and development of domain wall devices across a spectrum of ferroelectric materials.

This is an article in the field of metallurgical engineering. In order to explore the leaching mechanism of zinc oxide from zinc-containing dust by choline chloride and oxalic acid, the interaction of choline chloride and oxalic acid with 1∶1 and 1∶2 eutectic solvent on zinc oxide surface was simulated by means of quantum mechanics, and the simulation results were verified by experiments. The results show that the intermolecular hydrogen bond formed by choline chloride and oxalic acid plays an important role in the stability of eutectic solvent. Ch+ gains electrons, OA and Cl- lose electrons. ZnO(001) surface is the complete cleavage surface of zinc oxide, oxygen and zinc atoms form tetrahedral structure, oxygen atom is easy to gain electrons and zinc atom is easy to lose electrons during the reaction with the outside world. The zinc oxide loses electrons during the interaction between cholinergic chloride-oxalic acid and zinc oxide, and cholinergic chloride-oxalic acid gains electrons. The interaction energy △E=-819.6896Ha between ChCl-2OA and ZnO is small, indicating that zinc oxide is more likely to react with ChCl-2OA. The radial distribution function shows that the chemical adsorption is the main factor in the interaction between choline chloride and oxalic acid and zinc oxide, and the physical adsorption is the secondary factor. The contribution of Cl-Zn formed by chemical adsorption is greater than that of O-Zn. Through the pure mineral test, it can be verified that ChCl-2OA has a better leaching effect on zinc oxide, which verifies the accuracy of molecular simulation of the interaction mechanism between choline chloride and oxalic acid and zinc oxide, and provides a theoretical basis for the leaching of zinc-containing dust with eutectic solvent.

In this paper, the effect of C, N and O atom doping of intrinsic MoSe2 on the adsorption capacity of Ni is investigated based on first-principle research methods. The aim is to analyze whether intrinsic MoSe2 can be doped and modified to improve its adsorption capacity of Ni so that it can be used as a new type of adsorbent material. By calculating and analyzing the energy band structure, density of states, differential charge and optical properties of each system, the conclusions are as follows: the O-doped MoSe2 system has the best adsorption capacity for Ni, and the adsorption capacities of the three systems are in the following order: O>N>C. The bandgap value of intrinsic MoSe2 adsorbed Ni-atom decreases, while the Fermi energy level of the C-doped MoSe2 adsorbed Ni-atom system is located in the valence band, which shows p-type doping. The differential charge of the system was analyzed and the charge transfer of the adsorbed system was increased by C, N and O atom doping, and the O-doped system had the strongest adsorption capacity for Ni. It was shown that the charge distribution between the system and the adsorbed Ni-atom changed considerably after atomic doping, and the bonds between the Ni-atom and the dopant atoms of the C-, N- and O-doped adsorption system were strongly ionic. Optical analysis reveals that C, N and O atom doping improves the charge binding ability of Ni-adsorbed MoSe2 material, which gives it a higher polarization rate and faster electric field response. The absorption of ultraviolet light is greatly enhanced, which can improve the efficiency of solar cells and convert solar energy into electricity more effectively. Overall, the Ni adsorption capacity of atomically doped MoSe2 is improved, indicating that doping can be an effective means to improve the adsorption of Ni-atom by intrinsic MoSe2. It is hoped that the research results in this paper can provide some theoretical guidance for the application of MoSe2 in optoelectronic devices. [ABSTRACT FROM AUTHOR]

This study explores the potential of copper-doped nickel oxide (Cu:NiO) as a hole transport layer (HTL) in flexible photovoltaic (PV) devices using a combined first-principles and finite element analysis approach. Density functional theory (DFT) calculations reveal that Cu doping introduces additional states in the valence band of NiO, leading to enhanced charge transport. Notably, Cu:NiO exhibits a direct band gap (reduced from 3.04 eV in NiO to 1.65 eV in the stable supercell structure), facilitating the efficient hole transfer from the active layer. Furthermore, the Fermi level shifts towards the valence band in Cu:NiO, promoting hole mobility. This translates to an improved photovoltaic performance, with Cu:NiO-based HTLs achieving ~18% and ~9% power conversion efficiencies (PCEs) in perovskite and poly 3-hexylthiophene: 1-3-methoxycarbonyl propyl-1-phenyl 6,6 C 61 butyric acid methyl ester (P3HT:PCBM) polymer solar cells, respectively. Finally, a finite element analysis demonstrates the potential of these composite HTLs with Poly 3,4-ethylene dioxythiophene)—polystyrene sulfonate (PEDOT:PSS) in flexible electronics design and the optimization of printing processes. Overall, this work highlights Cu:NiO as a promising candidate for high-performance and flexible organic–inorganic photovoltaic cells. [ABSTRACT FROM AUTHOR]

In this paper, the microscopic mechanism and optical properties of nitric oxide (NO) molecules adsorbed on the surface of graphene were studied theoretically by using the first principles of plane wave ultra-soft pseudopotential calculation method based on density functional theory. In order to obtain more accurate results, the effects of dispersion interaction, long-range electron correlation effect and Van der Waals force are taken into account. The exchange correlation functional of DFT-D and generalized step approximation of PBE is used to optimize the geometric structure. The plane wave ultra-soft pseudopotential method is used to describe the interaction between electron and ion. The Kohn-Sham equation and the energy functional are solved by self-consistent method. According to the three adsorption sites on the surface of graphene - top site, bridge site and vacancy site, the adsorption model of NO molecules on the surface of 14 kinds of graphene was constructed. The adsorption energy, Mulliken distribution, differential charge density, state density and optical properties of NO molecules adsorbed on graphene surface were calculated. The results show that NO molecules are easily adsorbed on the surface of single-O doped, single-N doped and O-N double-doped graphene by chemical adsorption. All three kinds of doping will form a new impurity level near the Fermi level of graphene, which will help the electronic transition and improve the optical properties of graphene. In the range of visible light 360-780 nm, the optical properties of NO molecules adsorbed by C-N bond bridge site on the surface of O-N double-doped graphene are the best, and the peak absorption coefficient and reflection coefficient of O-N double-doped graphene are increased by about 1.40 times and 1.84 times, respectively, compared with that of undoped graphene. This work deepens the understanding of the process of NO molecule adsorption on graphene surface and its microscopic mechanism, and provides theoretical support for the study of NO sensing based on graphene materials. [ABSTRACT FROM AUTHOR]

The structures, stability and electronic properties of the Ni-doped boron nitride tubular clusters (NiBm−1Nm), NH3 adsorption on the NiBm−1Nm (NH3NiBm−1Nm) and NH3 embedded into the NiBm−1Nm (NH3@NiBm−1Nm) (m = 48, 72 and 96) clusters have been investigated by using density functional theory. The results reveal that the diameters of the NiBm−1Nm clusters have almost no effect on the NH3 adsorption. The diameter of the NiB47N48 clusters is small enough to accommodate the NH3 molecules, and the appropriate diameter of the NiB71N72 clusters occurs to embed the NH3 molecules. The NH3 molecules prefer to adsorb on rather than embed into the NiBm−1Nm clusters. The charge transfer between the NH3 molecules and the NiBm−1Nm clusters is limit, in the range of 0.002–0.221 |e|. The adsorption between the NH3 molecules and the NiBm−1Nm clusters is chemical process. In a word, the curvature effects of the Ni-doped boron nitride nanotubes with various diameters on NH3 adsorption are restrict. [ABSTRACT FROM AUTHOR]

To mitigate the greenhouse effect and environmental pollution caused by the consumption of fossil fuels, recent research has focused on developing renewable energy sources and new high-efficiency, environmentally friendly energy storage technologies. Among these, Li–CO2 batteries have shown great potential due to their high energy density, long discharge plateau, and environmental friendliness, offering a promising solution for achieving carbon neutrality while advancing energy storage devices. However, the slow kinetics of the CO2 reduction reaction and the accumulation of Li2CO3 discharge on the cathode surface lead to a significant reduction in space and active sites. This in turn results in high discharge overpotential, low energy efficiency, and low power density. This study elucidates the charge–discharge reaction mechanisms of lithium–carbon dioxide batteries and systematically analyzes their reaction products. It also summarizes the latest research advancements in cathode materials for these batteries. Furthermore, it proposes future directions and efforts for the development of Li–CO2 batteries. [ABSTRACT FROM AUTHOR]

The interfacial perpendicular magnetic anisotropy (PMA) observed at ferromagnet/oxide interfaces presents great promise for energy-efficient spintronic technologies. The epitaxial strain induced by the lattice mismatch between films and substrates serves as an effective strategy for the tuning of the material properties. However, the current understanding of the strain effects on interfacial PMA remains insufficient. Here, we present an extensive study of the biaxial strain effects on the interfacial magnetism and interfacial magnetic anisotropy constant ( K i ) in a slab-based Fe/MgO heterostructure using first-principles density functional theory calculations. Our results reveal a strong correlation between the spin moment of interfacial Fe atoms and the Fe-O bond length in both unstrained and strained systems. The overall K i , which includes contributions from both the Fe/MgO interface and the Fe surface, increases as the compressive strain increases. This is consistent with recent experimental findings that show that the PMA energy increases when the in-plane lattice constant of Fe decreases. In contrast, the overall K i initially decreases with a small tensile strain of less than 0.4% and shows an increasing trend as the tensile strain increases from 0.4% to 2%. However, beyond 2%, the overall K i decreases again. These changes in K i can be explained by the strain-induced variations of Fe 3d orbitals near the Fermi energy. This study provides a comprehensive understanding of the strain effects on magnetic anisotropy in Fe-based heterostructures, offering insights for the further optimization of interfacial magnetic properties. [ABSTRACT FROM AUTHOR]

Vanadium dioxide (VO2) is a thermally induced phase change material, the high phase change temperature restricts its potential application. Elemental doping can cause the changes in the properties of VO2 such as band structure, state density, bond length and cell volume, resulting in the change of phase transition behavior. Using Materials Studio software, based on first principles and molecular orbital theory, the crystal structure evolution and phase transformation mechanism of Gd and F doped VO2 were studied, it was found that no matter F doping in the middle O position of VO2 (M) or O position on both sides, the doping will cause O—O bond to contract, V—V bond to growth, β Angle to increase, system Helmholm self-energy to increase, band gap to be relative reduction, F on both sides of the doping effect is the best. With the decrease of V4+—V4+ unipolar bonding, the phase transition temperature reaches the lowest at 1at% F doping. When Gd is doped in V position in VO2 (M) at 0-1.8at%, O—O bond and V—V bond shrink, β Angle decreases, Helmholm self-energy increases, band gap decreases, and Gd 4f state coincides with tⅡ orbital, so that the phase transition energy barrier becomes lower and the phase transition temperature decreases significantly. The phase transition mechanism of gadolinium and fluorine doped VO2 is more consistent with Peierls-Mott synergistic phase transition. [ABSTRACT FROM AUTHOR]

In this paper, the lattice constants, elastic anisotropies, and elastic constants (C11, C12 and C44) of three Cs halide materials, CsCl, CsBr and CsI have been investigated for the first time by using first-principles-based calculations, and the bulk modulus (B), shear modulus (G), and Young's modulus (E) of the materials have been obtained based on the calculated elastic constants, and the mechanical properties of the materials have been analysed. The elastic anisotropy of the material is calculated and the corresponding three-dimensional surface diagram is drawn. The generalized stacking fault energy (GSFE) curves of CsCl, CsBr and CsI were calculated and the generalized stacking fault energy (GSFE) surfaces were fitted. The calculations show that the elastic constant results for CsCl, CsBr and CsI are fully consistent with the Born stability criterion, i.e., all three materials are consistent with good mechanical stability. The 3D surface images representing the dependence of the elastic properties on the crystal orientation more intuitively reflect the degree of anisotropy of the materials in agreement with the information reflected by the anisotropy factor. By comparing the generalized stacking fault energy (GSFE) surfaces in the three directions of the materials, it is found that the slip of CsI intermetallic is the hardest and the generalized stacking fault energy (GSFE) on the {110} plane has the laws of CsI > CsCl > CsBr along the < 100>, < 110 > and < 111 > directions. [ABSTRACT FROM AUTHOR]

Intermetallic compounds with B2 structure are used in aviation and aerospace, but lower ductilities are required for these materials. Here, to better understand the properties of this class of compound, the lattice constants of the intermetallic compounds AlSc and MgSc with B2 structure were calculated via first-principles methods, along with the their phase transition pressures. The generalized stacking energy curves of AlSc and MgSc at different pressures were also calculated, and the generalized stacking energy surface was fitted. The results reveal that, under pressure, < 111>{110} remains the sliding system of B2-type AlSc and MgSc. As the pressure increases, the antiphase boundary energies and unstable stacking fault energies of the two materials in all directions gradually increase. This means that the more energy required for dislocation in the process of sliding, the lower the ductility of the material. Comparing the phase change pressures of the two materials, it can be seen that AlSc has greater compressive resistance than MgSc, but for MgSc, at pressures lower than the phase change pressure, its ductility is greater than that of AlSc. [ABSTRACT FROM AUTHOR]