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Ultra-fast magic-angle spinning (100+kHz) has revolutionized solid-state NMR of biomolecular systems but has so far failed to gain ground for the analysis of paramagnetic organic and inorganic powders, despite the potential rewards from substantially improved spectral resolution. The principal blockages are that the smaller fast-spinning rotors present significant barriers for sample preparation, particularly for air/moisture-sensitive systems, and are associated with low sensitivity from the reduced sample volumes. Here, we demonstrate that the sensitivity penalty is less severe than expected for highly paramagnetic solids and is more than offset by the associated improved resolution. While previous approaches employing slower MAS are often unsuccessful in providing sufficient resolution, we show that ultra-fast 100+kHz MAS allows site-specific assignments of all resonances from complex paramagnetic solids. Combined with more reliable rotor materials and handling methods, this opens the way to the routine characterization of geometry and electronic structures of functional paramagnetic systems in chemistry, including catalysts and battery materials. We benchmark this approach on a hygroscopic luminescent Tb3+ complex, an air-sensitive homogeneous high-spin Fe2+ catalyst, and a series of mixed Fe2+/Mn2+/Mg2+ olivine-type cathode materials.

This paper investigates the tunable properties of two-dimensional spintronics and optoelectronics through V- and Fe-doping, alongside strain engineering. Using density functional theory, we focus on the impact of V- and Fe-doping and (V, Fe) co-doping, as well as strain engineering, on the electronic and optical properties of SnSe2. V and Fe atoms exhibit significant local magnetic moments of 2.86 µB and 3.20 µB, respectively. Our findings reveal that (V, Fe) co-doped SnSe2 is an indirect bandgap semiconductor with a bandgap of 0.367 eV. The ferromagnetic (FM) state, driven by the interaction between V and Fe 3d orbitals and Se 4p orbitals, is notably more stable, with a relative energy difference of − 388.30 meV. Additionally, 2% biaxial strain enhances the formation and stability of this FM state. The study also identifies a red-shift in the visible absorption spectrum, coupled with a weakening of intensity, resulting from the combined effects of doping and strain. These results demonstrate a promising strategy for the development of spintronic devices based on (V, Fe) co-doped SnSe2. [ABSTRACT FROM AUTHOR]

Ultra‐fast magic‐angle spinning (100+kHz) has revolutionized solid‐state NMR of biomolecular systems but has so far failed to gain ground for the analysis of paramagnetic organic and inorganic powders, despite the potential rewards from substantially improved spectral resolution. The principal blockages are that the smaller fast‐spinning rotors present significant barriers for sample preparation, particularly for air/moisture‐sensitive systems, and are associated with low sensitivity from the reduced sample volumes. Here, we demonstrate that the sensitivity penalty is less severe than expected for highly paramagnetic solids and is more than offset by the associated improved resolution. While previous approaches employing slower MAS are often unsuccessful in providing sufficient resolution, we show that ultra‐fast 100+kHz MAS allows site‐specific assignments of all resonances from complex paramagnetic solids. Combined with more reliable rotor materials and handling methods, this opens the way to the routine characterization of geometry and electronic structures of functional paramagnetic systems in chemistry, including catalysts and battery materials. We benchmark this approach on a hygroscopic luminescent Tb3+ complex, an air‐sensitive homogeneous high‐spin Fe2+ catalyst, and a series of mixed Fe2+/Mn2+/Mg2+ olivine‐type cathode materials. [ABSTRACT FROM AUTHOR]

Searching for controllable topological state by means of external stimuli in 2D material‐based van der Waals (vdW) heterostructures is currently an active field for both the underlying physics and practical applications. Herein, a vdW heterostructure formed by vertically stacking AlSb and InSe monolayers is designed and its stacking configuration, stability, electronic structure, and effect of external electric field are investigated using first‐principles calculations. The AlSb/InSe heterobilayer studied, possessing both dynamical and thermal stabilities, is direct bandgap semiconductor and forms a Z‐scheme heterojunction. With inclusion of spin–orbit coupling (SOC) and applying external electric field, the bandgap of AlSb/InSe heterobilayer decreases at first and then increases, and a trivial insulator to topological insulator phase transition is achieved. For the topological insulator phase, band inversion is ascribed to the strong SOC of p orbitals of Sb. In this work, the way is paved for the design and application of multifunctional nanoscale devices such as topological field‐effect transistor. [ABSTRACT FROM AUTHOR]

Monoclinic VO2, a semiconductor with a narrow bandgap, is highly suitable for infrared (IR) spectrum utilization. The electrical and optical properties of VO2 doped with X are thoroughly examined. Specifically, Mg doping decreases the formation of V–V dimers. The presence of the 3d orbitals of the V atoms and the 2s orbital of the Mg atom leads to a decrease in the bandgap. This leads to an absorption peak of 104 in the mid‐infrared (mid‐IR) range, resulting in an optical absorption that is approximately ten times greater than that of pure VO2. As a result, it becomes simpler to detect. Notably, the responsiveness of the system doped with Mg to IR light increases. VO2 significantly increases the photocurrent density, with a 1000‐fold increase in the mid‐IR region and a tenfold increase in the near‐IR region. This finding provides a theoretical basis for empirically exploring VO2 in IR technology. [ABSTRACT FROM AUTHOR]

The mechanical, electronic structure, and optical properties of lithium‐based perovskite LiMgX3 (X = Cl, Br, I) are investigated for the first time at 0–20 GPa using density‐functional theory. The Born stability criteria reveal that the phase transition points of LiMgCl3, LiMgBr3, and LiMgI3 are 20.7, 20.9, and 23.4 GPa, respectively. At 0 GPa, studies on the electronic properties using the Heyd‐Scuseria‐Ernzerhof (HSE06) functional show that LiMgCl3 and LiMgBr3 are indirect bandgap insulators with values of 5.336 and 4.113 eV, whereas LiMgI3 is an indirect bandgap semiconductor with a value of 2.055 eV. In addition, the bandgap calculated using both the PBEsol and HSE06 functionals decreases with increasing pressure, and the bandgap trends with pressure are consistent. Both functionals are also used to study the optical properties of LiMgX3 compounds, which show that they have potential for use in vacuum ultraviolet and photovoltaic applications. The mechanical and optical characteristics of the materials are significantly enhanced under pressure. [ABSTRACT FROM AUTHOR]

Understanding the influence of magnetism on thermal transport is crucial for ensuring the stability and reliability of heat dissipation in magnetic devices. In this study, we examine the magnetism's impact on thermal transport using the widely utilized Nd-Ce-Fe-B sintered magnet as our focal point. By integrating transient hot wire measurements and multiscale simulations, we assess how magnetism affects thermal conductivity (κ) between its ferromagnetic (FM) and paramagnetic (PM) states. Our analysis reveals that the thermal conductivity in the FM state is lower than in the PM state, indicating magnetism's inhibitory effect on thermal transport in Nd-Ce-Fe-B magnet. This phenomenon can be attributed to the suppressed electron transport in the FM state, which effectively reduces the electronic contribution to κ. To validate our findings, we conduct practical heating experiments at the device level alongside multiscale simulations. This research would significantly contribute to the understanding of thermal transport in magnetic materials, laying the groundwork for the thermal design of innovative devices that incorporate magnetism. [ABSTRACT FROM AUTHOR]

Ni3Sn4 intermetallic compound (IMC) is a critical material in modern electronic packaging and soldering technology. Although Ni3Sn4 enhances the strength of solder joints, its brittleness and anisotropy make it prone to crack formation under mechanical stress, such as thermal cycling or vibration. To improve the plasticity of Ni3Sn4 and mitigate its anisotropy, this study employs first-principles calculations to investigate the mechanical properties and electronic structure of the doped compounds Cex Ni3−xSn4 (x = 0, 0.5, 1, 1.5, 2) by adding the rare earth element Ce. The results indicate that the structure Ce0.5 Ni2.5Sn4 has a lower formation enthalpy ( H f ) compared to other doped structures, suggesting enhanced stability. It was found that all structures exhibit improved plasticity with Ce doping, while the Ce0.5 Ni2.5Sn4 structure shows relatively minor changes in hardness (H) and elastic modulus, along with the lowest anisotropy value ( A U ). Analysis of the total density of states (TDOS) and partial density of states (PDOS) reveals that the electronic properties are primarily influenced by the Ni-d and Ce-f orbitals. At the Fermi level, all Cex Ni3−xSn4 (x = 0, 0.5, 1, 1.5, 2) structures exhibit metallic characteristics and distinct electrical conductivity. Notably, the TDOS value at the Fermi level for Ce0.5 Ni2.5Sn4 lies between those of Ni3Sn4 and other doped structures, indicating good metallicity and conductivity, as well as relative stability. Further PDOS analysis suggests that Ce doping enhances the plasticity of Ni3Sn4. This study provides valuable insights for the further application of rare earth elements in electronic packaging materials. [ABSTRACT FROM AUTHOR]

Strain engineering is an effective approach for modulating the activity of single‐atom catalysts, yet the underlying mechanisms are not fully understood. This review focuses on the strain effects on single‐atom catalysts, detailing the geometric structure distortion and electronic structure changes of the active sites with different strains. It also discusses the mechanisms behind the modulation of electrocatalytic activity for single‐atom catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] The design strategy of designing effective local electronic structures of active sites to improve the oxygen evolution reaction (OER) performance is the key to the success of sustainable alkaline water electrolysis processes. Herein, a series of manganese-doped nickel molybdate porous nanosheets with rich oxygen vacancies on the nickel foam (Mn-NiMoO 4 /NF PNSs) synthesized by the facile hydrothermal and following annealing routes are used as high-efficiency and robust catalysts towards OER. By virtue of unique nanosheets architectures, more exposed active site, rich oxygen vacancies, tailored electronic structures, and improved electrical conductivity induced by Mn incorporation, as predicted, the optimized Mn 0.10 -NiMoO 4 /NF PNSs catalyst exhibits superior the OER performance with a low overpotential of 211 mV at 10 mA‧cm−2, a small Tafel slope of 41.7 mV‧dec-1, and an excellent stability for 100 h operated at 100 mA‧cm−2 in 1.0 M KOH electrolyte. The in-situ Raman measurements reveal the surface dynamic reconstruction. Besides, the results of density functional theory (DFT) calculations unveil the reaction mechanism. This study provides an effective design strategy via Mn incorporation to synergistically engineer electronic structures and oxygen vacancies of metal oxides for efficiently boosting the OER performance. [ABSTRACT FROM AUTHOR]

Recently, an effective syngas catalyst composed of AgZn3 clusters is reported, in which the CO and H2 generation may occur at the Zn sites and the hollow sites between Ag and Zn. Hence, the atomic model of the AgZn3 is worth established to further investigate the catalytic mechanism. Here, we take advantage of the genetic algorithm with the density functional theory to unbiasedly search configurations of (AgZn3)n (n = 1–6) clusters. It is found that (AgZn3)n clusters evolve from hollow cages to close-packed structures, with Zn atoms gradually occupying the core positions. The Eb and Δ2E analyses show that the (AgZn3)3 has a higher stability than that of its neighbors. The AIMD simulations demonstrate that the (AgZn3)3 shows a favorable stability at 700 K. The molecular orbitals reveal that 21 valence electrons of the (AgZn3)3 fill superatomic orbits resulting in an electronic configuration of 1S21P61D102S21F1. The adsorptions of CO on the bridge sites of (AgZn3)3 are much higher in energy than the top adsorptions, but the red shift of the stretching frequency of C-O is more obvious in the former. Our results are verified that the Zn sites and bridge sites between Ag and Zn are active sites for CO. [ABSTRACT FROM AUTHOR]

The reaction of Sn trace element with Ti will produce metal compounds and affect the mechanical properties of Ti‐Sn alloy. Herein, Ti‐xSn (x = 5, 10, 15, 20, 25 wt%) alloy is prepared by laser cladding technology. The phase composition is detected by X‐ray diffraction. The effects of pressure on the mechanical properties and electronic structures of Ti3Sn, Ti2Sn compounds, α‐Ti, and β‐Ti are calculated by first principles. The results show that there are four phases of Ti3Sn, Ti2Sn, α‐Ti, and β‐Ti in the alloy. The calculation shows that Ti2Sn has the highest Young's modulus (154.97 GPa) and hardness (837.75 HV), followed by α‐Ti and Ti3Sn, and β‐Ti has the lowest. The hardness calculation results show that Ti2Sn has the highest hardness (837.75 HV), α‐Ti (561.22 HV), and Ti3Sn (290.81 HV), and β‐Ti has the lowest hardness (128.57 HV). The electron accumulation of each phase increases with the increase of pressure, and the covalent bond of Ti3Sn and Ti2Sn is strengthened. In particular, the presence of Ti2Sn significantly improves the hardness of the Ti‐25Sn alloy. This research elucidates Ti‐Sn compound phase stability and hardness, confirms the accuracy of the first principle, and provides valuable insights for the design of alloy compositions. [ABSTRACT FROM AUTHOR]

Halide double perovskite semiconductors such as Cs2AgBiBr6 are widely investigated as a more stable, less toxic alternative to lead‐halide perovskites in light conversion applications including photovoltaics and photoredox catalysis. However, the relatively large and indirect bandgap of Cs2AgBiBr6 limits efficient sunlight absorption. Here, it is shown that controlled replacement of Bi3+ with Fe3+ via mechanochemical synthesis results in a remarkable tunable absorption onset between 2.1 and ≈1 eV. First‐principles density functional theory (DFT) calculations suggest that this bandgap reduction originates primarily from a lowering of the conduction band upon the introduction of Fe3+, and predict a direct bandgap when >50% of Bi3+ is replaced with Fe3+. The tunability of the conduction band energy is found and reflected in the photoredox activity of these semiconductors. These findings open new avenues for enhancing the sunlight absorption of double perovskite semiconductors and for harnessing their full potential in sustainable energy applications. [ABSTRACT FROM AUTHOR]

Topological surface states, protected by the global symmetry of the materials, are the keys to understanding various novel electrical, magnetic, and optical properties. TaSb2 is a newly discovered topological material with unique transport phenomena, including negative magnetoresistance and resistivity plateau, whose microscopic understanding is yet to be reached. In this study, we investigate the electronic band structure of TaSb2 using angle-resolved photoemission spectroscopy and density functional theory. Our analyses reveal distinct bulk and surface states in TaSb2, providing direct evidence of its topological nature. Notably, surface states predominate the electronic contribution near the Fermi level, while bulk bands are mostly located at higher binding energies. Our study underlines the importance of systematic investigations into the electronic structures of topological materials, offering insights into their fundamental properties and potential applications in future technologies. [ABSTRACT FROM AUTHOR]

The changes in the geometric structure,electrical structure,and optical characteristics of the substitution-doped MoSi2N4crystal with W,Mn,V,and Ti were estimated using the fundamental principles of density functional theory (DFT) .According to the electronic structure study,the prohibited band widths for W,Mn,W,and Ti doped two-dimensional MoSi2N4are 1.806 eV,1.003 eV,1.218 eV,and 1.373 eV,respectively.Given that the doping structure is a p-type semiconductor and that the impurity energy level is the dominant energy level,the impurity energy level introduced by W doping is close to the top of the valence band.Since the Fermi energy level and the impurity energy level are both near to the conduction band bottom and the doping structure is an n-type semiconductor,the impurity energy level introduced by Mn doping is also known as the sender energy level.The Fermi energy level,which is a part of the recombination center,is close to the impurity energy levels brought about by V and Ti doping.The optical property analysis shows that in the energy interval of2 eV～4 eV,the absorption wavelength of the W-doped structure is 336 nm and the system is red-shifted;the absorption wavelengths of the Mn-,V-and Ti-dopend systems are 320 nm,358 nm and 338 nm,respectively,and they are blue-shifted. [ABSTRACT FROM AUTHOR]

In this work, Density Functional Theory (DFT) is used to study pristine and defective GDY. We investigate the effect of Li atom adsorption on the electronic and structural properties of this 2D material. In both cases, the Li atom is located at the corner of the triangular‐like pore (H1), but with a slight shift for the defective system. In the perfect system, the Li−C bond distances range from 2.289 Å to 2.461 Å, while in the defective case, they range from 2.237 Å to 3.184 Å. In the perfect case, the GDY−Li system becomes metallic and the Li 2 s states are stabilized. Charge transfer to the surfaces occurs near the vicinity of the Li atom. The C vacancy generates new C=C bonds similar to double bonds, enhancing the interaction with Li through strong conjugation. After Li adsorption, the sum of bond order for all the C atoms increases in both structures, from 0.4 % to 6 %. The Li storage capacity without significant restructuring is six Li atoms. When the atom concentration increases, the OCV values for Li decrease from 0.93 V to 0.23 V. For defective GDY, the specific capacity is 788 mAhg−1, which is slightly higher than for pristine case. [ABSTRACT FROM AUTHOR]

Abstract Topological surface states, protected by the global symmetry of the materials, are the keys to understanding various novel electrical, magnetic, and optical properties. TaSb2 is a newly discovered topological material with unique transport phenomena, including negative magnetoresistance and resistivity plateau, whose microscopic understanding is yet to be reached. In this study, we investigate the electronic band structure of TaSb2 using angle-resolved photoemission spectroscopy and density functional theory. Our analyses reveal distinct bulk and surface states in TaSb2, providing direct evidence of its topological nature. Notably, surface states predominate the electronic contribution near the Fermi level, while bulk bands are mostly located at higher binding energies. Our study underlines the importance of systematic investigations into the electronic structures of topological materials, offering insights into their fundamental properties and potential applications in future technologies. Graphical Abstract

Topological surface states, protected by the global symmetry of the materials, are the keys to understanding various novel electrical, magnetic, and optical properties. TaSb2 is a newly discovered topological material with unique transport phenomena, including negative magnetoresistance and resistivity plateau, whose microscopic understanding is yet to be reached. In this study, we investigate the electronic band structure of TaSb2 using angle-resolved photoemission spectroscopy and density functional theory. Our analyses reveal distinct bulk and surface states in TaSb2, providing direct evidence of its topological nature. Notably, surface states predominate the electronic contribution near the Fermi level, while bulk bands are mostly located at higher binding energies. Our study underlines the importance of systematic investigations into the electronic structures of topological materials, offering insights into their fundamental properties and potential applications in future technologies.

Fe3GaTe2, a recently discovered van der Waals ferromagnet, demonstrates intrinsic ferromagnetism above room temperature, necessitating a comprehensive investigation of the microscopic origins of its high Curie temperature (TC). In this study, we reveal the electronic structure of Fe3GaTe2 in its ferromagnetic ground state using angle-resolved photoemission spectroscopy and density functional theory calculations. Our results establish a consistent correspondence between the measured band structure and theoretical calculations, underscoring the significant contributions of the Heisenberg exchange interaction (Jex) and magnetic anisotropy energy to the development of the high-TC ferromagnetic ordering in Fe3GaTe2. Intriguingly, we observe substantial modifications to these crucial driving factors through doping, which we attribute to alterations in multiple spin-splitting bands near the Fermi level. These findings provide valuable insights into the underlying electronic structure and its correlation with the emergence of high-TC ferromagnetic ordering in Fe3GaTe2.

2D carbon allotropes with moderated electronic bandgaps are highly desirable for next‐generation carbon‐based nanoelectronics beyond graphene. Herein, the structural and electronic properties of bilayer α‐graphyne have been systematically investigated by using first‐principles calculations. Consequently, in addition to typical van der Waals (vdW) stacks of single‐layer α‐graphyne, new 2D carbon allotropes with purely sp2 or sp3 hybridizations can be achieved, arising from the absence of intralayer acetylene linkages during structural relaxation. Compared to the Dirac semimetallic behavior of monolayer α‐graphyne, the electronic structure of vdW bilayer α‐graphyne can be further modulated by stacking patterns, yet retains metallic characteristics. In contrast, intrinsic semiconducting characteristics can be observed in the proposed new 2D carbon allotropes with tunable bandgaps dependent on the in‐plane biaxial strain. Correspondingly, a pristine 2D carbon sheet with only sp2 hybridization exhibits a promising direct bandgap of 1.062 eV, while the sp3‐hybridized carbon network possesses an indirect bandgap of 1.708 eV, which can be further converted to the direct type under small compressive strains, implying great potential in future carbon‐based nanoelectronic applications beyond graphene. Also, this work provides a new approach for developing novel carbon allotropes via the vertical stacking of graphyne with acetylenic linkages. [ABSTRACT FROM AUTHOR]

We investigate spin-polarized electronic structures of CoX2 (X = S, Se, and Te) monolayers using the density functional theory. We find that CoS2 and CoSe2 monolayers are metallic ferromagnetic materials, whereas CoTe2 monolayer is nonmagnetic metallic material. The 3D bulk layered crystalline structures of CoX2 (X = S, Se, and Te) are found to be nonmagnetic metals in our calculations. In addition to the major contributions due to the d orbitals of Co atoms, there is also contribution from the p orbitals of chalcogen X atoms to the electronic structure near the Fermi level of CoX2. We are optimistic for the experimental growth and uses of these monolayer structures for the 2D spintronic applications. [ABSTRACT FROM AUTHOR]

The optical properties of TiO2 are changed while doped with impurity atoms. This paper made a systematical calculation of the bandgap, the density-of-states (DOS), the optical properties for pure TiO2, and Bi-doped anatase TiO2 according to the first-principles plane wave ultrasoft pseudopotential method which is primarily based on the density functional theory (DFT). The calculation results exhibit that the bandgap decreased after doping, and the impurity energy level is produced into the bandgap of Bi-doped TiO2, which makes red-shift for the absorption band edge of Bi-doped TiO2 and the absorption is enhanced more in the visible light range. [ABSTRACT FROM AUTHOR]

This paper systematically investigates the electronic structure and optical properties of zinc-blende ZnTe, ZnS systems, ZnTe/ZnS heterojunctions, and Y-doped ZnTe/ZnS heterostructions using the generalized gradient approximation (GGA) method under the density functional theory (DFT) framework. The results show that compared to the single-component ZnTe or ZnS systems, the ZnTe/ZnS heterojunction has a smaller bandgap width and undergoes a redshift in the absorption spectrum, which is favorable for more valence band electrons to be excited by light and transition to the conduction band, thereby enhancing the optoelectronic properties of the material. After Y-doping in the ZnTe/ZnS heterojunction system, when the doping concentration is between 1.56 at% and 4.69 at%, doping Y in the ZnS layer would result in the lowest energy formation of the system. Therefore, it can be inferred that in experiments, if the doping concentration is increased beyond this range, Y atoms are more likely to be arranged in the ZnS layer. Compared with the pure ZnTe/ZnS heterojunction system, increasing the Y doping concentration results in a wider bandgap and a more prominent blue shift in the absorption spectrum. Therefore, it is possible to adjust the bandgap of the heterojunction by changing the doping concentration to fabricate heterojunction device with different photoelectric effects and luminescence properties. [ABSTRACT FROM AUTHOR]

The optical properties of TiO2 are changed while doped with impurity atoms. This paper made a systematical calculation of the bandgap, the density-of-states (DOS), the optical properties for pure TiO2, and Bi-doped anatase TiO2 according to the first-principles plane wave ultrasoft pseudopotential method which is primarily based on the density functional theory (DFT). The calculation results exhibit that the bandgap decreased after doping, and the impurity energy level is produced into the bandgap of Bi-doped TiO2, which makes red-shift for the absorption band edge of Bi-doped TiO2 and the absorption is enhanced more in the visible light range. [ABSTRACT FROM AUTHOR]

Recently, all‐inorganic halide double perovskites (DPs) with a chemical formula of Cs2BIBIIIX6 have been emerging as a shinning star to be used in modern optoelectronic devices, due to their unique advantages such as environmentally friendly, high absorption coefficient, low trap densities, tunable bandgap, variable constituent elements and valences states through BI or BIII sites engineering. In this review, first, the impact of BI and BIII cation doping on the electronic structure and optical properties of Cs2BIBIIIX6 DPs are systematically overviewed, which cover several key issues including the interconversion between direct and indirect band gaps, the enhancement of light absorption, promotion of exciton localization, elucidation of energy transfer mechanisms, regulation of defect density and improvement in both stability and luminescence efficiency. Subsequently, state‐of‐the‐art research activities regarding their interesting optoelectronic device applications are systematically discussed, such as light‐emitting diodes, anticounterfeiting encryption, X‐ray scintillators, and optical thermometry. Finally, the existing difficulties, prospects, and research directions in this field are proposed. [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]

The relationship between the composition of the internal defect states, spectral properties, and correlated electronic structures of wurtzite zinc oxide (ZnO) crystals under 645 MeV Xe35+ irradiation is systematically investigated, employing experimental characterizations combined with first‐principle calculations. Based on the ion irradiation‐induced thermal expansion and relaxation processes, the high concentration of vacancy/interstitial defects produced from the transient disordered phase in molten track states trigger photoelectric changes, as follows: i) the generation of internal defect states effectively reduces the intrinsic bandgap (3.25 eV → 2.66 eV); ii) a large number of defective active sites inhibits the recombination between electron–hole pairs, causing dark conductance and photoconductance to increase with increasing damage levels until optimal fluence is achieved. Based on the density functional theory (DFT) with the GGA + U (GGA = generalized gradient approximation) method, the defective models associated with the different electronic structures, density of states, formation energy, and the nature of the chemical bonding are established. The narrowing of the bandgap observed experimentally and the enhancement of carrier concentration originating from the internal electron defect states are qualitatively verified, therefore laying the foundation for designing future nanoscale photoelectronic devices and microelectronics applications. [ABSTRACT FROM AUTHOR]

Topological semimetals represent a novel class of quantum materials displaying non‐trivial topological states that host Dirac/Weyl fermions. The intersection of Dirac/Weyl points gives rise to essential properties in a wide range of innovative transport phenomena, including extreme magnetoresistance, high mobilities, weak antilocalization, electron hydrodynamics, and various electro‐optical phenomena. In this study, the electronic, transport, phonon scattering, and interrelationships are explored in single crystals of the topological semimetal HfAs2. It reveals a weak antilocalization effect at low temperatures with high carrier density, which is attributed to perfectly compensated topological bulk and surface states. The angle‐resolved photoemission spectroscopy (ARPES) results show anisotropic Fermi surfaces and surface states indicative of the topological semimetal, further confirmed by first‐principle density functional theory (DFT) calculations. Moreover, the lattice dynamics in HfAs2 are investigated both with the Raman scattering and density functional theory. The phonon dispersion, density of states, lattice thermal conductivity, and the phonon lifetimes are computed to support the experimental findings. The softening of phonons, the broadening of Raman modes, and the reduction of phonon lifetimes with temperature suggest the enhancement of phonon anharmonicity in this new topological material, which is crucial for boosting the thermoelectric performance of topological semimetals. [ABSTRACT FROM AUTHOR]

Herein, the effect of different atomic vacancies on the properties of C40‐type WSi2 are investigated. The formation energy, elastic properties, phonon, electronic structure, thermodynamic, and optical properties of C40‐type WSi2 are calculated. Calculations reveal that W vacancies are more likely to form in WSi2, and no imaginary phonon frequencies are detected in the phonon dispersion curves. Vacancies slightly enhance the ductility of C40 WSi2, with W vacancies performing better than Si vacancies. These vacancies weaken the W—Si and Si—Si bond strengths, affecting the elastic modulus but increasing the ductility of WSi2. The electronic properties indicate that C40‐WSi2 is a semiconductor. From the electronic structure analysis, it is clear that the W atomic vacancy can transform WSi2 from semiconducting‐to‐metallic properties. The effects of vacancies on the thermodynamic and optical properties of WSi2 are explored. This research contributes to the development of excess metal silicides as potential high‐temperature materials for later use. [ABSTRACT FROM AUTHOR]

The edge reconstruction of two‐dimensional (2D) materials is significant for the stability, properties, and applications. Significant progress has been made in understanding the edge reconstruction of 2D materials. Herein, an overview of the latest theoretical and experimental advances on edge reconstruction of α‐phase phosphorene nanoribbon and IV–VI group binary compounds MX (M = Ge, Sn; X = S, Se), focusing on the mechanism, stability, physical, and chemical properties of the edge reconstructions is provided. The status, challenges, and contradictions in experiments and theory are addressed and the progress in edge reconstruction of α‐phase puckered 2D materials as well as the effects of edge reconstruction on physicochemical properties are systematically introduced. A novel tube‐like edge reconstruction is suggested to be universal for α‐phase puckered monolayers. While ZZ(U) edge can be another important reconstruction in bilayer. Beyond the review, the edge structures of phosphorene have odd–even layered oscillations are also proposed. The edge terminations can affect the exfoliation mechanism and electronic, transport properties. Interesting, unique U‐edge, which has been verified by experiment, exhibits nearly edgeless electronic and thermal transport, which is beneficial for ultrafast microelectronics. [ABSTRACT FROM AUTHOR]

Polar surfaces are prevalent in metal oxides, the interactions between surface species with polar surfaces are different from those with non-polar surfaces, a thorough understanding of the interactions is key to regulate the performance of heterogeneous catalysts. In this work, we delve into the interaction of Ptn (n=1–4) with polar ZnO(0001)-Zn and ZnO(000 1 ¯)-O, and the influence of the surface polarity on the electronic structures and reactivity of Ptn by using density functional theory calculations. The results suggest distinct differences in electronic structures of two exposed terminations, leading to different interactions with Ptn. The interaction between Ptn and two terminations not only stabilizes the surface and clusters through polar compensation, but also induces opposite charges on the cluster at two terminations. Remarkably, the Pearson correlation coefficient reveals the interdependency between the electronic states of Ptn and its performance in terms of small molecule adsorption/activation. These observations demonstrate the crucial role of surface polarity in regulating the electronic states and catalytic performance of active sites, and offer a possible design principle for supported catalysts. [ABSTRACT FROM AUTHOR]

In this study, a sulfur–phosphorus co‐doped nanocarbon (SPC) catalyst was synthesized using a straightforward one‐step colloidal carbonization method and demonstrated high performance in the metal‐free direct oxidation of alcohols to aldehydes. This metal‐free SPC catalyst showed exceptional efficiency, achieving a conversion rate of 90% for benzyl alcohol and a selectivity of 94% toward benzaldehyde within only 1 h at 130°C. Moreover, it displays exceptional cycle stability and a high turnover frequency (17.1 × 10−3 mol g−1 h−1). Theoretical analysis suggested that the catalyst's superior performance is attributed to the presence of unsaturated edge defects and S−P− moieties, which increase the density of states at the Fermi level, lower the band gap energy, and promote electron localization. Additionally, the doping introduces cooperative co‐active S−P−C sites, facilitating a synergistic multisite catalytic effect that lowers the energy barriers. These findings represent a significant advancement in the field of metal‐free direct alcohol oxidation. [ABSTRACT FROM AUTHOR]

Using density functional theory combined with nonequilibrium Green's function, the electronic structures and carrier transport properties of the orthorhombic phase boron nitride nanoribbons (BNNRs) with different edges and different widths are investigated. The calculated results show that both armchair‐ and zigzag‐edged BNNRs are direct bandgap semiconductors. The quantum confinement gives rise to a distinct bandgap for the 1D BNNRs, and the edged atoms play an important role on their electronic structures. The bandgaps of the armchair‐edged BNNRs approach 0.5–0.8 eV when their widths are sufficiently large. However, the electronic structures of the zigzag‐edged BNNRs exhibit more variations dependent on their edged atoms. The J–V characteristics of the BNNRs reveal that the zigzag‐edged BNNRs have superior J–V performance to that of the armchair‐edged counterparts. Eventually, a computational nanodevice design is proposed to achieve rectifying behavior by constructing an in‐plane heterojunction based on the BNNRs without any doping, and the left and right electrodes are formed by differently edged atoms and a small strain is performed on the left electrode. The rectification ratio of about 77.36 is realized. The findings provide comprehensive understandings of the orthorhombic BN monolayer, which can be helpful to its potential application for nanoelectronics. [ABSTRACT FROM AUTHOR]

Herein, lead‐free, mixed‐halide perovskites of cesium bismuth bromide/iodide are synthesized by a hydrothermal method, and their structures and optical properties of the solid solution compounds are examined. The synthesized compounds exhibit X‐ray diffraction patterns similar to that of trigonal Cs3Bi2Br9 (CBB), whose reflections are shifted to lower angles depending on the experimental iodine content. Very interestingly, even with the excessive introduction of iodine content in nominal, the symmetry of the crystals is kept to be trigonal, indicating that bromide CBB and iodide Cs3Bi2I9 (CBI) are crystallographically mixed in a facile way, although the stable crystal form of CBI is hexagonal. The optical properties of bandgap energy Eg and photoluminescence (PL) for the synthesized crystals are also examined. It is found that Eg decreases and PL peak position is correspondingly shifted to a longer wavelength with an increase in the experimental iodine content due to their band‐to‐band transitions. Moreover, first‐principles calculation suggests the reduction of Eg with iodine content and the varied nature of band structure from direct (trigonal CBB) to indirect (trigonal CBI) transition. These novel findings can make the proposed strategy successful for developing lead‐free, mixed‐halide Bi‐based perovskite crystals with the tunability of their optical properties. [ABSTRACT FROM AUTHOR]