Abstract Like full or half-heusler materials, equiatomic quaternary Heuslers (EQH) also display various intriguing physical properties. We carried out the strict and rigorous density functional theory calculations to estimate the...
moreAbstract Like full or half-heusler materials, equiatomic quaternary Heuslers (EQH) also display various intriguing physical properties. We carried out the strict and rigorous density functional theory calculations to estimate the stability of novel ferrimagnetic FeMnTaAl alloy. In this work, we considered the thermodynamic, energetic, dynamic and mechanical stability criteria, by evaluating the formation energy, phonon dispersion and elastic constants, respectively, which thereby suggest that the synthesis of FeMnTaAl as bulk phase is likely. Later, the electronic structure, magnetic and transport properties are determined from the ground state parameters. After the structural optimizations, the half-metallic character from spin resolved band structures and local spin moments (1 μB) potentially felicitate its spintronic applications. Conservative estimates of Seebeck coefficient (~85 μV/K at 900 K), lattice thermal conductivity (2.8 W/mK at 300 K) and figure of merit (0.03 at 900 K) have also been put forward in this report. The overall structural stability, ferrimagnetism with large TC accompanied by transport properties will possibly enact the experimental realization for magnetic, thermoelectric or spintronic impressions of this material in future.
By incorporating the nonempirical SCAN semilocal density functional [Sun, Ruzsinszky, and Perdew, Phys. Rev. Lett. 115, 036402 (2015)] in the underlying expression of four existing hybrid and double-hybrid models, we propose one hybrid...
moreBy incorporating the nonempirical SCAN semilocal density functional [Sun, Ruzsinszky, and Perdew, Phys. Rev. Lett. 115, 036402 (2015)] in the underlying expression of four existing hybrid and double-hybrid models, we propose one hybrid (SCAN0) and three double-hybrid (SCAN0-DH, SCAN-QIDH, and SCAN0-2) density functionals, which are free from any fitted parameters. The SCAN-based double-hybrid functionals consistently outperform their parent SCAN semilocal functional for self-interaction problems and noncovalent interactions. In particular, SCAN0-2, which includes about 79% of Hartree-Fock exchange and 50% of second-order Moller-Plesset correlation, is shown to be reliably accurate for a very diverse range of applications, such as thermochemistry, kinetics, noncovalent interactions, and self-interaction problems.
Abstract Here we discuss the electronic structure and optical properties of Yb based halide perovskites with keen interest on phonon and mechanical stability using the HSE06 approximated density functional theory calculations. The...
moreAbstract Here we discuss the electronic structure and optical properties of Yb based halide perovskites with keen interest on phonon and mechanical stability using the HSE06 approximated density functional theory calculations. The experimental structural parameters are exploited to calculate the semiconducting band structures with energy gap of 4.32 eV and 3.68 eV for CsYbCl3 and CsYbXBr3 alloys, respectively. Cubic phase stability is guaranteed by the phonon dynamics and machinability of these structures. The observed relaxed structural parameters are in accord with the previous experiments. We found that the present halide perovskite compounds are semiconductors with tuneable band gaps and the f-states of Yb element play a significant role in defining the electronic structure. In addition to this, the sound velocities accompanied by the Debye temperatures (181 K for Cl and 141 K for Br) are evaluated. Furthermore, the dielectric constant optical conductivity, electron loss function, refractive index provide a fundamental basis of the feasible optical characteristics suitable for optoelectronic devices and applications.
Thermally assisted occupation density functional theory (TAO-DFT) has been an efficient electronic structure method for studying the ground-state properties of large electronic systems with multi-reference character over the past few...
moreThermally assisted occupation density functional theory (TAO-DFT) has been an efficient electronic structure method for studying the ground-state properties of large electronic systems with multi-reference character over the past few years. To explore the time-dependent (TD) properties of electronic systems (e.g., subject to an intense laser pulse), in this work, we propose a real-time (RT) extension of TAO-DFT, denoted as RT-TAO-DFT. Moreover, we employ RT-TAO-DFT to study the high-order harmonic generation (HHG) spectra and related TD properties of molecular hydrogen H2 at the equilibrium and stretched geometries, aligned along the polarization of an intense linearly polarized laser pulse. The TD properties obtained with RT-TAO-DFT are compared with those obtained with the widely used time-dependent Kohn–Sham (TDKS) method. In addition, issues related to the possible spin-symmetry breaking effects in the TD properties are discussed.