Aspects of simulating metal-insulator transitions in CrS and CoS

• Published in: Bulletin of the Russian Academy of Sciences. Physics 2014-08, Vol.78 (8), p.694-697
• Main Authors: Lavrentyev, A. A., Gabrelian, B. V., Shkumat, P. N., Nikiforov, I. Ya
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Band gap; Computer simulation; Conductors; Crystal structure; Electron spin; Electron states; Hadrons; Heavy Ions; Insulators; Metal-insulator transition; Nuclear Physics; Physics; Physics and Astronomy; Proceedings of the International Symposium “Environments with Structural and Magnetic Ordering” Multiferroics 4; Three dimensional models
• ISSN: 1062-8738; 1934-9432
• DOI: 10.3103/S1062873814080231

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 3 d -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 3 d 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.