The Quasiparticle Electronic Energy Bands of the Cubic KMgF₃ Perovskite under Pressure Effect

First-principles calculations have been carried out to study the electronic properties of the KMgF₃ perovskite crystal. On first stage the calculations were performed within the generalized gradient approximation. On the second stage we have evaluated the quasiparticle corrections to the generalized gradient approximation band structure. These significantly improved electronic energies have been found here for the first time on base of the quasiparticle approach as implemented in the ABINIT code. Also, the pressure dependent parameters of electronic energy band spectra were found in the generalized gradient approximation. For the first time the pressure dependent electronic band energies have been evaluated within the quasiparticle approach. The generalized gradient approximation band gap parameters are in good agreement with the literature data, obtained with local density approximation or generalized gradient approximation exchange-correlation functionals and are much underestimated compared with the experiment. The quasiparticle band gap agrees well with the measured value.