Modelos efetivos e fatores giromagnéticos via DFT2kp e funcionais híbridos

Abstract

The Density Functional Theory (DFT) and the k · p method are two important techniques for calculating the electronic band structures of crystalline materials, which is fundamental for studying their electronic, optical, and transport properties. The DFT2kp package inte- grates DFT and the k·p method by implementing computational routines for the automatic construction of effective k · p models from ab initio data generated by DFT calculations. In this work, we investigated how the hybrid functional Heyd–Scuseria–Ernzerhof 2006 (HSE06) influences the values of the parameters (effective mass, g-factors, and Dresselhaus constant) extracted from effective k · p models for GaAs. To this end, DFT calculations were performed using both the semilocal Perdew–Burke–Ernzerhof Generalized Gradient Approximation (PBE-GGA) functional and the hybrid HSE06 functional in various config- urations. The results show that the HSE06 functional yields band gaps and k · p model parameters that are more accurate than those obtained with the semilocal functional. It was also observed that these parameters are sensitive to adjustments of the tunable HSE06 parameters. Finally, an analysis of the variation of the k · p parameters as a function of the band gap was carried out, demonstrating that applying a scissor-shift to PBE-GGA calculations can produce results similar to those obtained with HSE06, suggesting that in applications tolerating some inaccuracy, the high computational cost of HSE06 may not be justified.