Multiband k·p model and fitting scheme for ab initio based electronic structure parameters for wurtzite GaAs

Abstract

We develop a 16-band k • p model for the description of wurtzite GaAs, together with a scheme to determine electronic structure parameters for multiband k • p models. Our approach uses low-discrepancy sequences to fit k • p band structures beyond the eight-band scheme to most recent ab initio data, obtained within the framework for hybrid-functional density functional theory with a screened-exchange hybrid functional. We report structural parameters, elastic constants, band structures along high-symmetry lines, and deformation potentials at the point. Based on this, we compute the bulk electronic properties (point energies, effective masses, Luttinger-like parameters, and optical matrix parameters) for a ten-band and a sixteen-band k • p model for wurtzite GaAs. Our fitting scheme can assign priorities to both selected bands and k points that are of particular interest for specific applications. Finally, ellipticity conditions can be taken into account within our fitting scheme in order to make the resulting parameter sets robust against spurious solutions.

Strain Effects in Wurtzite Boron Nitride: Elastic Constants, Internal Strain, and Deformation Potentials from Hybrid Functional Density Functional Theory

“…We begin with the deformation potentials. These parameters are key ingredients when calculating the electronic and optical properties of semiconductor heterostructures in the frame of semi‐empirical atomistic approaches (e.g., tight‐binding [ 3 ] ) or continuum‐based models (like theory [ 5 ] ). We note however that care must be taken when deriving deformation potentials from our DFT data, especially for use in models.…”

“…In principle, to model its electronic structure with theory, more bands must be considered, e.g., 16 bands as recently done for WZ GaAs. [ 5 ] In contrast, experimental studies indicate that BN contents of only can be incorporated in III‐N materials. [ 22 ] Furthermore, even if the higher BN‐content regime (where a direct‐to‐indirect band gap cross‐over may occur [ 14,23 ] ) becomes accessible in the future, the low‐BN‐content, direct‐gap region is expected to remain of strong relevance for the design of quantum‐well (QW) active regions in optoelectronic device applications.…”

“…Overall, to drive the understanding of fundamental properties but also to design future devices, theoretical modeling is an essential ingredient. Here, density functional theory (DFT) plays an important role, since: 1) it can provide insight into the fundamental material properties from first principles and 2) the insight obtained can form the basis and input for developing empirical atomistic [3,4] but also continuum-based [5,6] models that allow for simulating full device structures.…”

Strain and crystal field splitting inversion in III-Nitrides

“…New k.p Hamiltonians to get the correct description of both valence and conduction bands, due to improvement of computational efforts, has been proposed recently [25][26][27] . Despite the fact that, the spin-orbit interactions can be considered negligible in most semiconducting materials, its inclusion helps to identify, correctly, the symmetry character of the top valence states and, thus, giving a correct description of the band states, as shown in the recent work done by Bastos and collaborators for the semiconducting zincblende structure 26 .…”

“…Considering the improvement of k.p modelling for wurtzite band structures, initial efforts in this direction were done by Marquardt et al 27 . In their new k.p model, more bands were evaluated from the Density Functional Theory (DFT) results (16 ones in their new model, but 8 of them were located at the conduction band) than the earlier attempts to obtain the k.p parameters.…”