Cost-Effective Hybrid Density Functional Theory Calculation of Three-Dimensional Band Structure and Search of Band Edge Positions

Abstract

Accurate calculation of the electronic band structure is essential to material screening and design. Hybrid density functional has been recently widely used to describe the electronic structure of semiconductors; however, it is difficult to locate the band edge positions of indirect band gap materials due to heavy computational cost especially when the band edges are not located at special k-points. We suggest how to investigate three-dimensional band structure efficiently with hybrid density functionals and to find the band edge positions. The band edge position of diamond Si, SbSI, and MoS 2 are investigated using the proposed method.

Search of chalcopyrite materials based on hybrid density functional theory calculation

“…Here we note that the electronic band gap was obtained by using a 6 × 6 × 6 k-point grid. In calculations with finer k-point mesh, the band gap should be calculated to be equal to or lower than the reported value [45].…”

“…Here the computation cost was reduced by setting the downsampling factor for the Fock exchange potential to 2 [42]. Our previous studies show that this approach reduces the computation cost of the hybrid DFT calculation without losing much accuracy [31,[43][44][45]. In other words, when a 6 × 6 × 6 k-point grid is employed with the downsampling factor of 2, a downsampled 3 × 3 × 3 grid was used for the Fock exchange potential.…”

Inorganic Cs2TeX6 (X = Cl, Br, I) Lead-Free Vacancy-Ordered Double-Perovskite Absorber-Based Single-Junction Solar Cells with a Higher Efficiency of ∼24%: Theoretical Insights

“…Initially, the complex dielectric function ε(ω), i.e., ε ( ω ) = ε r ( ω ) + normali ε i ( ω ) is computed in the range of 0–5 eV, which is the sum of its real (ε r ) and imaginary (ε i ) parts. It provides a linear response to the electromagnetic interaction and is correlated to E g Figure a displays the imaginary part (ε i ) of the dielectric function, which is computed using the momentum matrix elements integrated over the Brillouin zone (BZ) and is proportional to the absorption spectra.…”

“…It provides a linear response to the electromagnetic interaction and is correlated to E g . 75 Figure 5a displays the imaginary part (ε i ) of the dielectric function, which is computed using the momentum matrix elements integrated over the Brillouin zone (BZ) and is proportional to the absorption spectra. At threshold energies, ε i shows optical transitions from VBM to CBM, which are ∼3.02, 2.48, and 1.65 eV for the Cl-, Br-, and I-based Cs 2 TeX 6 systems, respectively.…”