Electronic structure and dielectric function of Mn-Bi-Te layered compounds

• Published in: Journal of vacuum science and technology. B, Nanotechnology & microelectronics Vol. 37; no. 6
• Main Authors: Jahangirli, Zakir A., Alizade, Elvin H., Aliev, Ziya S., Otrokov, Mikhail M., Ismayilova, Narmin A., Mammadov, Samir N., Amiraslanov, Imamaddin R., Mamedov, Nazim T., Orudjev, Guseyn S., Babanly, Mahammad B., Shikin, Alexander M., Chulkov, Evgueni V.
• Format: Journal Article
• Language: English
• Published: 01.11.2019
• ISSN: 2166-2746; 2166-2754
• DOI: 10.1116/1.5122702

A comparative study of the electronic and optical properties of Mn-Bi-Te layered compounds was carried out using spectroscopic ellipsometry (SE) over a photon energy range of 0.7–6.5 eV at room temperature and density functional theory (DFT)-based first-principle calculations within the general gradient approximation with Hubbard like correction (GGA+U) and allowance for a spin-orbital coupling. The total energies of the above compounds in ferromagnetic (FM) and antiferromagnetic (AFM) spin configurations are obtained by taking the long-range van der Waals interaction into account. The stability of the AFM state of MnBi2Te4 and MnBi4Te7 over the corresponding FM counterpart is disclosed. The SE-based and calculated dielectric functions are compared. It is shown that interband optical transitions in the accessed photon energy range mainly occur between Mn 3d + Te 5p states of the valence band and Bi 6p + Te 5p with a small admixture of Mn 3d states of the conduction band.