Journals
2026 EN
Rahman Ata Ur · Ikram Muhammad · Hussain Ghulam
+1 more
ABSTRACT Although 2DMA 2 Z 4 ${\rm MA}_2{\rm Z}_4$ materials exhibit exceptional physical properties, their bulk counterparts remain largely unexplored. In this study, we conduct a comprehensive theoretical investigation of the structural stability, mechanical characteristics, electronic, and optical properties of bulkMoSi 2 P 4 ${\rm MoSi}_2{\rm P}_4$ andWSi 2 P 4 ${\rm WSi}_2{\rm P}_4$ , representative members of theMA 2 Z 4 ${\rm MA}_2{\rm Z}_4$ family, to assess their feasibility and stability in bulk form. Ground‐state energy calculations identify AB stacking as the most stable configuration, while ab initio molecular dynamics (AIMD) and phonon analyses indicate the thermodynamic stability of bulkMoSi 2 P 4 ${\rm MoSi}_2{\rm P}_4$ andWSi 2 P 4 ${\rm WSi}_2{\rm P}_4$ structures. Furthermore, the calculated elastic constants and derived moduli validate the mechanical stability of both bulk materials, in accordance with the Born stability criteria. We find that bulkMoSi 2 P 4 ${\rm MoSi}_2{\rm P}_4$ and WSi 2 P 4 are semiconductors with indirect bandgaps of 0.89 (1.65) and 0.78 (1.50) eV, respectively, as calculated using PBE (HSE06) functionals. The dielectric function analysis reveals strong optical anisotropy, with high static dielectric constants,ε x x = 17.6 $\varepsilon _{xx} = 17.6$ (19.2) andε z z = 12.7 $\varepsilon _{zz} = 12.7$ (12.5) forMoSi 2 P 4 ${\rm MoSi}_2{\rm P}_4$ (WSi 2 P 4 ${\rm WSi}_2{\rm P}_4$ ). Both materials exhibit distinct absorption peaks in the infrared and ultraviolet regions, highlighting their excellent potential for optoelectronic applications. In addition, high refractive indices and strong plasma resonances (19.5–19.6 eV) heir potential for photonic and IR devices. Overall, the findings support the experimental realizability of bulkMA 2 Z 4 ${\rm MA}_2{\rm Z}_4$ materials, paving the way for their potential synthesis and integration into practical devices.
Journals
2026 EN
Mohammadi Mahnaz
Abstract Mercury is a dangerous heavy metal for the environment and human health. In this study, density functional theory (DFT) is employed to investigate the effect of the transition metals (TM) decoration on the C 2 N for Hg 0 removal applications. These findings indicate that the adsorption energy of Hg 0 on the C 2 N surface is low (−0.16 eV), however, the Mn, Fe, and Co atoms decoration on the C 2 N monolayer can enhance the adsorption energy. Specifically, the Fe@C 2 N exhibits the highest Hg 0 adsorption energy. The work function of the C 2 N monolayer increases after the adsorption of the Hg 0 and TM, due to the surface charge density redistribution. The impact of the Hg 0 coverage and the number of the Fe atoms on the adsorption energy is also studied. The optimal number of the Hg 0 atoms adsorbed on the Fe@C 2 N is two, while the Fe 3 cluster decorated on the C 2 N monolayer can accommodate three Hg atoms. The presence of the CO molecule cannot affect Hg 0 adsorption on the Fe@C 2 N, but the presence of the H 2 O molecule causes the surface to bend. This study can provide insight into the application of the C 2 N monolayer for Hg 0 removal and provides a deep understanding of the adsorption process.
Journals
2026 EN
Vero Khoveto · Borah J. P.
Abstract This study presents a details analysis of the electronic structure, stability, and magnetic properties of MnGa alloys. The effects of 3 d transition metal (Ti, V, Cr, Fe, Co, Ni, Cu, and Zn) substitution in Mn sites of MnGa alloys at varying concentrations ( x = 0.12, 0.25, 0.37, and 0.50) have been examined. The findings show that substitution does not positively impact these materials' magnetic characteristics. Specifically, MAE decreases for all substituted materials, suggesting that 3d transition metal (TM) substitution in MnGa alloys is not a desirable strategy. To explore alternative ways to enhance MAE, the doping of lighter elements (N, B, and C) at interstitial sites are investigated. It is found that N doping in the interstitial site of L1 0 ‐MnGa significantly enhances MAE, reaching a high value of 4.03 MJ m − 3 , along with a high saturation magnetization ( µ o M s ) of 1 T, a maximum energy product (BH) max of 28.16 MGOe and a Curie temperature ( T C ${T_C}$ ) of 611 K. These properties make it a promising candidate to compete with rare‐earth‐based permanent magnets. However, the magnetic properties of L1 0 ‐Mn 1.66 Ga and D0 22 ‐Mn 3 Ga alloys are not enhanced by TM substitution or doping with lighter elements. This work offers a thorough examination of how compositional changes affect the electronic, structural, and magnetic properties of MnGa alloys, providing valuable insights for the design of rare‐earth‐free permanent magnetic materials for future technological applications.
Journals
2026 EN
Bhowmick Arka · Venkatakrishnan Kanchana
ABSTRACT Departing from conventional band theory, topological materials are classified by topological invariants, a fundamental property that reliably ensures the presence of robust boundary states. This intrinsic characteristic renders their surface electrons immune to disorder‐induced localization. We delve into the theoretical underpinnings of this topological protection in NaCdBi. Our first‐principles calculations reveal Pnma NaCdBi as a potential topological material (TM) exhibiting a distinct Dirac‐like crossing point at the surface along the Γ $\Gamma$ ‐X path. Furthermore, the value of its topological invariant quantity suggests it to be a non‐trivial strong topological material. We point out that NaCdBi shows an anisotropic Spin Hall Conductivity (SHC) with the largest componentσ z y x $\sigma _{zy}^x$ reaching approximately −502( ℏ / e hbar /e)$ S/cm. The findings from our work contribute to understanding the emergence of considerable spin Hall effects in this compound. Anisotropic spin Hall conductivity enables directional control of spin currents, offering a pathway to tunable spintronic devices. In anisotropic magneto‐optical materials, this spin manipulation can, in turn, modulate light and control polarization, opening new avenues for photonic applications.
Journals
2026 EN
Murari Himanshu · Ghosh Subhradip
Abstract Reduction in symmetry has emerged as an effective approach to better the transport parameters in 2D materials. Motivated by this, using Density Functional Theory and Boltzmann transport theory, the thermoelectric properties of the Janus monochalcogenidesGe 2 XY ${\rm Ge}_{2}{\rm XY}$ ,Sn 2 XY ${\rm Sn}_{2}{\rm XY}$ , andGeSnX 2 ${\rm GeSnX}_{2}$ (X, Y = S, Se, Te) derived from parent group IV‐VI chalcogenides MX (M = Ge, Sn; X = S, Se, Te) that have turned out to be promising thermoelectric materials, are investigated. It is found that while the unconventional band structures of these Janus compounds lead to highly anisotropic, increased anharmonicity and reduced phonon group velocity contribute to the low lattice thermal conductivity of these compounds. The combination of multivalley and pudding mold features in electronic band structures enhances the power factor (PF), resulting in optimal thermoelectric figure of merit of 1.61 (1.62), 1.70 (1.61), and 1.56 (0.84) for n‐type (p‐type)Ge 2 STe ${\rm Ge}_{2}{\rm STe}$ ,Sn 2 SeTe ${\rm Sn}_{2}{\rm SeTe}$ , andGeSnSe 2 ${\rm GeSnSe}_{2}$ , respectively, at 800 K. The results suggest that these Janus compounds are promising materials for thermoelectric applications.
Journals
2026 EN
Abdulmahdi Mohanad Ahmed · AlKhursan Amin Habbeb
ABSTRACT This work studies four‐wave mixing (FWM) in a double quantum dot (DQD)‐metal nanoparticle (MNP) system. Two control optical waves and a weak probe are applied. The probe is characterized by its orbital angular momentum (OAM) light optical properties. An analytical form of the probe and the generated FWM signal is obtained using spatial‐temporal equations. A high second control field reduces efficiency, thereby increasing the FWM signal. At weak coupling DQD‐MNP, the first coupling field increases the efficiency, and a near‐complete conversion is attained. Such a result is unprecedented and arises from the DQD's properties, where the manipulation between DQD states is high and the DQD behaves as a whole system. Weak coupling gives high efficiency. Such a result refers to the direct effect of the controlling fields on the FWM conversion. The OAM number increases the probe and FWM fields. A fast light is obtained, and the group‐velocity peak is shifted under a strong control field. While both complete conversion and fast light are observed at the earliest, other results are within the range reported in the literature. The results obtained are essential for many critical applications.
Journals
2026 EN
Vibert Amadéo · Daanoune Mehdi · Rafhay Quentin
+1 more
Abstract Micro Light‐Emitting Diodes (MicroLEDs) are expected to penetrate the display market and allow for the development of augmented reality (AR) or virtual reality (VR) technologies. InGaN/GaN nanowires are very promising for these applications, thanks to their high luminescence and emission directivity. However, there is still room for significant improvement of the efficiency of these 3D nanostructures. This study presents a numerical simulation of multiple quantum well (MQW) nanowires in Light‐Emitting Diodes (LEDs). Using a Poisson‐drift‐diffusion solver, the tuning of the injection efficiency for multiple geometries and material variations will be presented. It is found that the injection of holes through the multiple planes of nanowires always follows a lateral injection through the semi‐polar planes into polar quantum wells, that needs to be optimized to ensure radiative recombination in the first quantum wells. The ratio of polar/semi‐polar plane quantum wells length is a key factor in the design of nanowires, and the Wall‐Plug Efficiency (WPE) significantly varies with the size of semi‐polar quantum wells. Furthermore, the impact of degraded recombination area at the top and bottom of the nanowire confirms that a careful choice in the quantum well number must be carried out. The design of optimal and efficient InGaN/GaN nanowires, hence, reveals complex trade‐offs, adjustable through controlled epitaxial growth.
Journals
2026 EN
Jatkar Mandar · Shah Arpan · Hegde Shubha
+1 more
Abstract This study investigates the electronic properties of Thallium Nitride Nanoribbons (ThNNRs) in bare, pristine, and functionalized forms using density functional theory (DFT). The influence of nanoribbon width on structural stability and electronic characteristics is also examined. Bare ThNNRs exhibit metallic behavior with a zero bandgap, whereas pristine ThNNRs display semiconducting behavior, with their bandgap decreasing as the ribbon width increases. Functionalization with sensing molecules such as BF 3 , NO 2 , and CO 2 significantly alters the electronic response. In particular, NO 2 ‐ and CO 2 ‐functionalized ThNNRs undergo a semiconductor‐to‐metallic phase transition with increasing width. Sensitivity analysis reveals that sensitivity decreases with temperature, indicating an inverse relationship. Recovery time analysis shows that ThNNRs–BF 3 and ThNNRs–CO 2 configurations are minimally affected by temperature. In contrast, ThNNRs–NO 2 exhibits strong temperature dependence, with recovery times peaking at 34.13 s at 500 K. These findings demonstrate the tunable electronic properties of ThNNRs and underscore their potential in nanoelectronics and chemical sensing applications.
Journals
2026 EN
Zhao Jingcheng · Li Nan · Wang Dong
+1 more
Abstract Spatial spectral filters, also known as frequency‐selective surfaces, have consistently been in high demand in the past decades due to their diverse and extensive applications across numerous fields. Here, a design and comprehensive analysis of a broadband, high‐transmission metasurface (MS) bandpass filter (BPF) is presented that incorporates an ABA tri‐layer structure. Tailored for X‐band applications, this BPF utilizes electromagnetic (EM) wave tunneling and strong magnetic field coupling to deliver exceptional performance. The unit cell of the BPF is composed of a square‐aperture (SA) situated between two identical layers of four‐square‐patches (FSPs), sandwiched between dielectric substrates. The experimental results reveal that the designed BPF demonstrates a transmission coefficient exceeding −3 dB within the frequency range of 9.06–11.14 GHz, achieving a relative bandwidth of 20.6%. This performance closely aligns with the predictions obtained from both the equivalent circuit model (ECM) and the finite element method (FEM) simulation, thereby validating the accuracy and effectiveness of the design approach. Additional numerical simulations have verified that the designed BPF exhibits robust performance across a broad range of incident angles, encompassing both transverse electric (TE) and transverse magnetic (TM) polarizations. Given its exceptional transmission characteristics, the proposed MS BPF demonstrates promising potential for X‐band radome applications.
Journals
2026 EN
Okamoto Takuma · Kameda Keisuke · Wang Hao
+2 more
Abstract Grain boundaries (GB) affect properties of polycrystalline ceramics, including mechanical and electronic properties. While often individual postulated GBs are considered in atomistic models, a distribution of GBs present in real ceramics should be accounted for. An often‐used method to build polycrystalline models is geometry‐based Voronoi tessellation. With it, random grain orientations generally obtain in atomistic models of GBs with non‐physically high Miller index grain surfaces. Recently, models of polycrystalline rutile TiO 2 were constructed with molecular dynamics (MD) using computational heat treatment, a procedurally nature‐like approach resulting in a distribution of GBs dominated by low‐index surfaces. It is important to understand the similarities and differences in GB‐affected properties with MD‐ and Voronoi tessellation‐based models for informed selection of an appropriate model for specific applications. Such a comparison is presented. Structural properties and the effect of grainy structures on mechanical properties and band structure are compared. High‐index surfaces prevalent in Voronoi structures lead to the formation of amorphous interlayers, and fracture stress is lower than with MD‐based structures. Band structures of GBs are analyzed in large‐scale electronic structure calculations. It is found that while low‐index surfaces do not result in trap states, high‐index surfaces and amorphous interlayers may introduce such states.