Aspects of simulating metal-insulator transitions in CrS and CoS
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The electron-energy structure of CrS and CoS monosulfides at a temperature of 0 K is investigated theoretically using the augmented plane wave approach in combination with the WIEN2k program code. Computations of the total and partial densities of electron states are performed in the LDA + U approximation with allowance for the antiferromagnetic ordering of magnetic moments of 3d-metal atoms. In our models, the optical forbidden band gap E g in the CrS compound emerges in the monoclinic crystal structure but is missing from the NiAs structure. For the CoS compound in the NiAs structure, computations of the electron-energy structure are performed for both the highand low-spin configurations of the Co atom’s 3d 7 shell. The optically forbidden E g band gap appears in the high-spin configuration with strong correlations of d-electrons, while CoS remains a conductor in the low-spin configuration.
KeywordsSpin Polarization Nonlocal Parameter Metallic Conduction Spin Configuration Strong Electron Correlation
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