Theoretical Investigations on the Molecular Magnetic Behavior of Actinide Molecules [AnPc] (An = U, Cf): Prediction of the High Magnetic Blocking Barrier and Magnetic Blocking Temperature in [CfPc].

Searching for single-molecule magnets (SMM) with large effective blocking barriers, long relaxation times, and high magnetic blocking temperatures is vitally important not only for the fundamental research of magnetism at the molecular level but also for the realization of new-generation magnetic memory unit. Actinides (An) atoms possess extremely strong spin-orbit coupling (SOC) due to their 5 orbitals, and their ground multiplets are largely split into several sublevels because of the strong interplay between the SOC of An atoms and the crystal field (CF) formed by ligand atoms. Compared to TM-based SMMs, more dispersed energy level widths of An-based SMMs will give a larger total zero field splitting (ZFS) and thus provide a necessary condition to derive a higher .

Editorial for two-dimensional materials-based heterostructures for next-generation nanodevices.

Heterostructures, such as van der Waals (vdW) heterostructures, provide a versatile platform for engineering the physical properties of two-dimensional (2D) layered materials, spanning electronics, mechanics, optics, as well as electron-phonon couplings. Furthermore, vdW heterostructures, which are composed of metal/semiconductor or semiconductor/semiconductor combinations, not only maintain the unique properties of their individual constituents but also exhibit tunable physical and chemical properties that can be externally adjusted through strain, heat, and electric fields. These externally tunable properties offer significant advances in the fields of solid-state devices and renewable energy applications.

Prediction of the two-dimensional ferromagnetic semiconductor Janus 2H-ZrTeI monolayer with large valley and piezoelectric polarizations.

Two-dimensional room-temperature Janus ferrovalley semiconductors with valley polarization and piezoelectric polarization offer new perspectives for designing multifunctional nanodevices. Herein, using first-principles calculations, we predict that the Janus 2H-ZrTeI monolayer is an intrinsic ferromagnetic semiconductor with in-plane magnetic anisotropy and a Curie temperature of 111 K. The Janus ZrTeI monolayer possesses a significant valley polarization of 141 meV due to time-reversal and inversion symmetry breaking.

Two-Dimensional GeC/MXY (M = Zr, Hf; X, Y = S, Se) Heterojunctions Used as Highly Efficient Overall Water-Splitting Photocatalysts.

Hydrogen generation by photocatalytic water-splitting holds great promise for addressing the serious global energy and environmental crises, and has recently received significant attention from researchers. In this work, a method of assembling GeC/MXY (M = Zr, Hf; X, Y = S, Se) heterojunctions (HJs) by combining GeC and MXY monolayers (MLs) to construct direct Z-scheme photocatalytic systems is proposed. Based on first-principles calculations, we found that all the GeC/MXY HJs are stable van der Waals (vdW) HJs with indirect bandgaps.

Theoretical Determination of the Electronic Structures and Energy-Level Splitting for Pr-Doped YSiO Crystals.

Trivalent praseodymium (Pr)-doped yttrium silicate (YSiO) crystals have been widely used in various phosphors owing to their excellent luminescence characteristics. Although a series of studies have been carried out on its application prospects, the electronic structures and energy-transfer mechanisms of Pr-doped YSiO (YSiO:Pr) remain an exploratory topic. Herein, the crystal structure analysis by the particle swarm optimization structure search method is used to study the structural evolution of YSiO:Pr.

Prediction of a two-dimensional high Curie temperature Weyl nodal line kagome semimetal.

Kagome lattices may have numerous exotic physical properties, such as stable ferromagnetism and topological states. Herein, combining the particle swarm structure search method with first-principles calculations, we identify a two-dimensional (2D) kagome MoSe crystal structure with space group 6/. The results show that 2D kagome MoSe is a 100% spin-polarized topological nodal line semimetal and exhibits excellent ambient stability.

Electric Field-Controlled Magneto-Optical Kerr Effect in A-Type Antiferromagnetic FeCX (X = F, Cl) and Its Janus Monolayer.

The magneto-optical Kerr effect (MOKE) is a powerful probe of magnetism and has recently gained new attention in antiferromagnetic (AFM) materials. Through extensive first-principles calculations and group theory analysis, we have identified FeCX (X = F, Cl) and Janus FeCFCl monolayers as ideal A-type collinear AFM materials with high magnetic anisotropy and Néel temperatures. By applying a vertical external electrical field () of 0.

Excellent 5f-electron magnet of actinide atom decorated gh-CN monolayer.

Atomic functionality of two-dimensional (2D) materials, typically with a controllable doping route for offering regular atomic arrangement as well as excellent magnetism, is crucial for both fundamental studies and spintronic applications. Here, the adsorptions of the 5f-electron actinide series (An = Ac-Am) on porous graphene-like carbon-nitride (gh-CN) layers are explored to determine their structural stabilities, electronic nature and magnetic properties using the combination of density functional theory (DFT) calculations, molecular dynamics (AIMD), Monte Carlo (MC) simulations and chemical bonding analyses. Our investigations reveal that each An atom can be individually adsorbed at the vacancy site of gh-CN sheet with high energetic, thermal and dynamical stabilities, which are rooted in the major interactions of ionic An-N bonding as well as the minor interactions of covalent bonding of An-5f6d states with N-2s2p states.

Photoluminescence and energy transfer mechanisms of Tm doped YO laser crystals: experimental and theoretical insights.

Rare-earth thulium (Tm) doped yttrium oxide (YO) host single crystals are promising "eye-safe" laser materials. However, the mechanisms of photoluminescence and energy transfer in Tm doped YO crystals are not yet understood at the fundamental level. Here, we synthetize a series of YO:Tm samples by the sol-gel method.

Thermoelectric response of single quintuple layer sodium copper chalcogenides persisting at high temperature.

The thermoelectric transport properties of two-dimensional (2D) layered NaCuX (X = S, Se) are investigated by employing first-principles based Boltzmann transport theory. Single quintuple NaCuX layers have a relatively large Seebeck coefficient (), electrical conductivity () and hence power factor (PF = ) for a p-type heavy doped region due to the valence band degeneracy. The largely reduced by dominant polar scattering leads to a PF up to 0.

High thermoelectric performance of two-dimensional layered ABTe (A = Sn, Pb; B = Sb, Bi) ternary compounds.

The thermoelectric properties of two-dimensional layered ternary compounds ABTe, in which A (Sn, Pb) and B(Sb, Bi) are group-IV and group-V cations, respectively, were investigated by using first-principles based transport theory. These septuple-atom-layer monolayers have wider band gaps with respect to their bulks, which extend their operating temperature and inhibit the bipolar carrier conduction and thermal conductivity, and more importantly, their energy bands exhibit multiple valence band convergence to a narrow energy range near the Brillouin zone center, which induces an optimal p-type power factor up to 10.94-32.

Electronic structure, magnetoresistance and spin filtering in graphene|2 monolayer-CrI3|graphene van der Waals magnetic tunnel junctions.

In the pursuit of designing van der Waals magnetic tunneling junctions (vdW-MTJs) with two-dimensional (2D) intrinsic magnets, as well as to quantitatively reveal the microscopic nature governing the vertical tunneling pathways beyond the phenomenological descriptions on CrI-based vdW-MTJs, we investigate the structural configuration, electronic structure and spin-polarized quantum transport of graphene|2 monolayer(2ML)-CrI|graphene heterostructure with Ag(111) layers as the electrode, using density functional theory (DFT) and its combination of non-equilibrium Green's function (DFT-NEGF) methods. The in-plane lattice of CrI layers is found to be stretched when placed on the graphene (Gr) layer, and the layer-stacking does not show any site selectivity. The charge transfer between CrI and Gr layers make the CrI layer lightly electron-doped, and the Gr layer hole-doped.

A two-dimensional PtS/BN heterostructure as an S-scheme photocatalyst with enhanced activity for overall water splitting.

Photocatalytic hydrogen production from water is a sustainable solution to the environmental pollution and energy crises. Encouraged by the successful synthesis of PtS and BN nanosheets and their suitable band edges, we have designed a PtS/BN bilayer heterojunction and investigated its electronic and optical properties for the first time based on hybrid DFT calculations. In this system, the built-in electric field and band edge bending can retain useful electrons on the conduction band of BN and holes on the valence band of PtS, which endow this system with a stronger redox ability.

Intrinsic spin, valley and piezoelectric polarizations in room-temperature ferrovalley Janus Ti ( = SCl and SeBr) monolayers.

Two-dimensional room-temperature Janus ferrovalley semiconductors with large spin, valley and piezoelectric polarizations provide fertile platforms for designing multifunctional nanodevices. Little research has been reported to date on such materials. Here, using first-principles calculations, we predict two dynamically stable Janus titanium chalcohalide (TiSCl and TiSeBr) monolayers, which are excellent piezoelectric ferrovalley semiconductors with in-plane magnetization and high magnetic transition temperatures (738 and 884 K).

Above-room Curie temperature and barrier-layer-dependent tunneling magnetoresistance in 1T-CrO monolayer based magnetic tunnel junctions.

van der Waals (vdW) heterostructures based on two-dimensional (2D) ferromagnetic materials hold great potential applications in spintronics. Using the density functional theory (DFT) method and first-principles quantum transport simulation, we studied the structures, magnetic properties and spin-resolved transport of 1T-CrO monolayer (ML) based vdW magnetic tunnel junctions (MTJs). Owing to a high Curie temperature () of 392 K and a moderate magnetic anisotropy energy (MAE) of 94 μeV of the ferromagnetic 1T-CrO monolayer, Cu(111)|CrO|ML-Gr|CrO|Cu(111) MTJs were built.

A Hybrid Functional Study on Perovskite-Based Compounds CsPbZnIX (X = Cl or Br).

Inorganic perovskites have attracted a great deal of attention because of their stability. Unfortunately, a weak optical response and the toxicity of lead are hampering their development. Motivated by these facts, we focus herein on the perovskite-based doped series CsPbZnIX (X = Cl or Br).

Dual-Metal Active Sites Mediated by p-Block Elements: Knowledge-Driven Design of Oxygen Reduction Reaction Catalysts.

In this study, the oxygen reduction reaction (ORR) process of dual-metal active site catalysts (FeMN-Gra, M = Mn, Ni, Co, or Cu) mediated by p-block elements was investigated using density functional theory calculations. The obtained results demonstrate that, in most cases, the B-doped FeMN-Gra (M = Mn, Ni, Co, or Cu) catalysts exhibit higher catalytic performance than their undoped counterparts. Among the investigated catalysts, FeNiN-Gra doping by B modulates the adsorption strength of the metal center on the oxygen-containing intermediates, showing the largest increase in the onset potential (from 0.

Rational design of M-N-Gr/VC heterostructures as highly active ORR catalysts: a density functional theory study.

Inspired by the composites of N-doped graphene and transition metal-based materials as well as MXene-based materials, heterostructures (M-N-Gr/VC) of eight different transition metals (M = Ti, Cr, Mn, Fe, Co, Ni, Cu, and Zn) doped with nitrogen-coordinated graphene and VC as potential catalysts for the oxygen reduction reaction (ORR) using density functional theory (DFT) were designed and are described herein. The calculations showed that the heterostructure catalysts (except for Zn-N-Gr/VC) were thermodynamically stable. Ni-N-Gr/VC and Co-N-Gr/VC showed higher activities towards the ORR, with overpotentials as low as 0.

A study on hydrogen storage performance of Ti decorated vacancies graphene structure on the first principle.

The structural properties, formation energy, adsorption energy, and electronic properties of vacancy graphene are studied by first-principles analysis. We found that the formation energy and adsorption energy of double vacancy graphene (DVG-4) are the largest. A single defect in DVG-4 can adsorb at least nine hydrogen molecules, and compared with Ti modified single vacancy graphene (SVG-Ti), the adsorption capacity is increased by 80%.

Monolayer gadolinium halides, GdX (X = F, Cl, Br): intrinsic ferrovalley materials with spontaneous spin and valley polarizations.

Two-dimensional (2D) intrinsic ferrovalley semiconductors provide unprecedented opportunities to investigate valley physics as well as providing promising device applications due to their exceptional combination of spontaneous spin and valley polarizations. Here, we have predicted from first-principles calculations and Monte Carlo simulations that monolayers (MLs) GdX are such extremely rare excellent materials. Apart from their robust stabilities energetically, dynamically, thermally, and mechanically, these 2D materials are found to be semiconducting intrinsic ferromagnets where the magnetic coupling is ascribed to 5d-electron-mediated 4f-4f exchange interactions.

Two-dimensional CdS/SnS heterostructure: a highly efficient direct Z-scheme water splitting photocatalyst.

A desired water splitting photocatalyst should not only possess a suitable bandgap and band edge position, but also host the spontaneous progress for overall water splitting without the aid of any sacrificial agents. In this work, we propose a two-dimensional CdS/SnS heterostructure (CSHS) as a possible water splitting photocatalyst by first-principles calculations. The CSHS enhances the absorption of visible and infrared light, and the type-II band alignment guarantees the spatial separation of the photoinduced carriers.

Hourglass Weyl and Dirac nodal line phonons, and drumhead-like and torus phonon surface states in orthorhombic-type KCuS.

In parallel to electronic systems, the concept of topology has been extended to phonons, which has led to the birth of topological phonons. In this Communication, based on symmetry analysis and first-principles calculations, we propose that hourglass Weyl nodal line (HWNL) phonons and Dirac nodal line (DNL) phonons coexist in the phonon dispersion of a single material, KCuS, with a -type structure. The HWNLs and DNLs are relatively flat in frequency and well separated from other phonon bands.

Study of photogenerated exciton dissociation in transition metal dichalcogenide van der Waals heterojunction A2-MWS: a first-principles study.

In order to explore the photocatalytic hydrogen production efficiency of the MoS/WSe heterostructure (A2-MWS) as a photocatalyst, it is highly desirable to study the photogenerated exciton dissociation related to photocatalysis. The electronic properties, optical absorption, and lattice dynamic properties of A2-MWS were investigated using a first-principles approach. The results show that the type II energy band alignment of A2-MWS facilitates the dissociation of photogenerated excitons (electrons and holes).