Effect of Strong Correlations on the Spin-polarized Electronic Energy Bands of the CdMnTe Solid Solution

The influence of strong d-electron correlations on the values of the parameters of the electron energy bands in the solid solution Cd1-xMnxTe (x ( 0.25) was studied. At the first stage, the spin-resolved electronic energy bands were obtained in the GGA approach. At the second stage, strong correlations were taken into account for the Mn d-electrons by means of the hybrid exchange-correlation function PBE0, and at the third stage, correlations of the Mn and Cd d-electrons were included simultaneously. It was revealed that the material is a semiconductor for both spin channels. Found that for spin-up electrons, after taking into account the strong correlations of the Mn 3d-electrons, the top of the valence band was shifted by – 0.10 eV, and the bottom of the conduction band has increased by 0.02 eV, which resulted in an increase in the band gap, Eg, by 0.12 eV. Strong correlations of the Cd 4d-electrons add to an increase in Eg a value of 0.03 eV. The total increase in Eg for spin-up electrons is equal to 0.15 eV. For the spin-down electrons, the inclusion of strong 3d-electron correlations of Mn led to an increase in the top of the valence band by 0.12 eV, and the bottom of the conduction band has increased by 0.54 eV, resulting in an increase in the band gap by 0.42 eV. Strong correlations of the Cd 4d-electrons add to an increase in Eg a value of 0.02 eV. The total increase in Eg for spin-down states equals 0.44 eV. It was found that for spin-up electrons, the value of Eg of solid solution, without taking into account strong correlations of d-electrons, is 1.32 eV, and the inclusion of 3d-electron correlations of Mn leads to the Eg value of 1.44 eV. And the additional inclusion of 4d-electron correlations of Cd gives the Eg value of 1.47 eV. It was found that for spin-down electrons, the value of Eg of a solid solution, without taking into account the strong correlations of d-electrons, is 1.69 eV, and the inclusion of 3d-electron correlations of Mn leads to the Eg value of 2.11 eV. And the accounting of 4d-electron correlations of Cd has caused only a slight increase in the Eg to 2.13 eV.Keywords: Solid solution, Strong correlation, Electronic energy bands, Spintronics.