Articles
Publication Date: 2026
Optical Materials: X (25901478)29
We report a first-principles investigation of the structural, electronic, and optical properties of NaBiXY (X, Y=S, Se, Te) ternary chalcogenides, with a focus on optical anisotropy and pressure response. Total energy and formation energy calculations reveal that all compounds, except NaBiS2 and NaBiSe2, favor a trigonal crystal structure over the cubic NaCl-type phase. All systems exhibit indirect band gaps, with values tunable through chalcogen substitution. NaBiTe2 presents the smallest gap, while NaBiSeS has the largest. Band gap variation under hydrostatic pressure is nearly linear across the series. Optical property analysis shows pronounced dielectric anisotropy, particularly in the low-energy region below 6 eV, with the in-plane component (εxx) exceeding the out-of-plane component (εzz). Substituting Te with Se or S shifts the primary peaks of the dielectric function to higher photon energies with reduced intensity. The optical spectra remain stable under moderate pressure, highlighting environmental robustness. These results identify NaBiXY compounds as promising pressure-resilient and compositionally tunable semiconductors with directional optical behavior, suitable for future photonic and optoelectronic applications © 2025 The Authors
Publication Date: 2025
Nanomaterials (20794991)15(2)
The present work investigates the interfacial and atomic layer-dependent mechanical properties, SOC-entailing phonon band structure, and comprehensive electron-topological–elastic integration of ZrTe2 and NiTe2. The anisotropy of Young’s modulus, Poisson’s ratio, and shear modulus are analyzed using density functional theory with the TB-mBJ approximation. NiTe2 has higher mechanical property values and greater anisotropy than ZrTe2. Phonon dispersion analysis with SOC effects predicts the dynamic stability of both compounds. Thus, the current research unifies electronic band structure analysis, topological characterization, and elastic property calculation to reveal how these transition metal dichalcogenides are influenced by their structural, electronic, and mechanical properties. The results obtained in this work can be used in the further development of spintronic and nanoelectronic devices. © 2025 by the authors.
Publication Date: 2025
Materials Science and Engineering: B (09215107)315
The structural, electronic, mechanical properties, and phonon dispersions of lithium-based intermetallic compounds Li2PdX (X = Ga, Ge, In), Li2InPt, Li2InAu, and LiPd3 are investigated using density functional theory (DFT) via the Wien2k code. Stability is analyzed through energy-volume curves, cohesive and formation energies, elastic tensor components, and phonon density of states. Hydrostatic pressure effects on stability and mechanical properties are also examined. The results confirm the stability of these compounds in nonmagnetic cubic phases, with calculated lattice parameters and bulk moduli in agreement with existing data, validating the computational approach. Phonon density of states analysis establishes the dynamical stability of Li2PdGa and Li2PdGe in space group Fm3¯m (No. 225); Li2InPt, Li2InAu, and Li2PdIn in F4¯3m (No. 216); and LiPd3 in Pm3¯m (No. 221). Elastic properties reveal a critical pressure point (Pt) beyond which mechanical instability occurs. Around Pt, Pugh's ratio (bulk-to-shear modulus ratio) exhibits limiting behavior, persisting as long as C44 is comparable to C11-C12. However, for LiPd3, a marked reduction in C44 near Pt eliminates this behavior, underscoring its distinct mechanical response. A derived limit for Pugh's ratio offers new insights into the elastic behavior of these materials under extreme conditions. Electronic properties, including the density of states and linear electronic specific heat coefficient, confirm the metallic nature of these compounds. These findings provide valuable insights into the pressure-dependent mechanical and electronic behavior of lithium-based intermetallic compounds, informing their potential applications in energy storage, electronic devices, and pressure-sensing. © 2025
Publication Date: 2025
Physical Chemistry Chemical Physics (14639084)27(8)pp. 4407-4418
Two-dimensional (2D) materials have garnered significant attention for their exceptional potential in electronic, optical, and flexible nanodevices. In this study, we introduce a novel 2D In2F2 monolayer, revealed through first-principles calculations, and demonstrate its thermal, dynamic, and mechanical stability. Our findings show that the In2F2 monolayer exhibits notable anisotropic mechanical behavior, including auxetic properties characterized by a negative Poisson's ratio. Electronic band structure calculations, using both PBE-GGA and HSE06 functionals, indicate that this monolayer is a semiconductor with a small, nontrivial topological bandgap of approximately 1.58 meV. The observed s-p band inversion and calculated invariant, confirm the presence of a nontrivial topological phase in this material. Furthermore, the optical absorption spectrum reveals strong anisotropy, with significant absorption in the visible to near-infrared range along the y-axis, suggesting potential applications in polarized photodetectors and anisotropic optoelectronic devices. The relatively low work function (3.86 eV) further increases its suitability for electron-emission applications, such as thermionic devices. These mechanical, electronic, and optical properties position the In2F2 monolayer as a promising candidate for next-generation electronics, flexible electronics, and anisotropic optoelectronics. © 2025 The Royal Society of Chemistry.
Publication Date: 2025
Journal of Materials Chemistry C (20507534)13(38)pp. 19749-19762
Exploring new two-dimensional (2D) materials with unique electronic and topological properties is key to developing next-generation electronic devices. We predict, using first-principles density functional theory calculations, a novel two-dimensional (2D) material, the K2Be2P2 monolayer with a square Bravais lattice, and investigate its structural, electronic, mechanical, and optical properties. Our comprehensive stability analyses, encompassing phonon dispersion, cohesive energy (−3.1 eV per atom), formation energy (−2.46 eV per atom), elastic constants, and ab initio molecular dynamics, confirm that K2Be2P2 is dynamically, thermodynamically, and mechanically stable, suggesting its experimental realizability. While initial PBE-GGA calculations suggest a near-zero bandgap, more accurate HSE06 hybrid functional calculations reveal that pristine K2Be2P2 is a direct-bandgap semiconductor with a gap of 165 meV at the Γ point. Crucially, we demonstrate that the application of biaxial compressive strain induces a topological phase transition (TPT) from a trivial insulator to a topological insulator. This TPT, occurring at approximately −2% strain, is characterized by bandgap closure and reopening, accompanied by p-p type band inversion near the Fermi level. The topological nature of the strained phase is unambiguously confirmed by the topological invariant () and the presence of topologically protected edge states, calculated using a semi-infinite Green's function approach. Furthermore, we find that K2Be2P2 exhibits in-plane mechanical anisotropy, with a relatively low Young's modulus (68.59 N m−1), suggesting potential for flexible electronics applications. The optical properties, characterized by the frequency-dependent dielectric function, reveal strong absorption in the visible and near-infrared regions, with a pronounced anisotropy dependent on light polarization, and an exceptionally low work function of 1.49 eV. Our findings position K2Be2P2 as a promising candidate for strain-engineered topological phase transitions in two-dimensional materials, showcasing the tunability of its electronic and topological properties for next-generation electronic and spintronic devices. © 2025 The Royal Society of Chemistry.
