No abstract

Narrow bandgap Bi2Se3, Bi2Te3, and Sb2Te3, commonly referred to as classic 3D topological insulators, were studied at room temperature by spectroscopic ellipsometry and optical reflection spectroscopy over the mid-IR–near-infrared photon energy range. Complementarily, Hall measurements were performed. Plasmons in optical loss function and reflection coefficient were identified. The conventional approach based on the high frequency dielectric constant was shown to work well in the description of plasmons in Bi2Se3 and Sb2Te3 and to fail in the case of a similar compound, Bi2Te3. The obtained results are discussed in terms of single- and multivalley approaches to the studied samples with taking the details of the calculated band structure into account.

The phase equilibria in the MnGa 2 Tе 4 -MnIn 2 Tе 4 system were experimentally investigated by means of differential thermal analysis and powder X-ray diffraction technique. It was found that this system is quasi-binary and characterized by dystectic and eutectic equilibria and the formation of a wide area of solid solutions based on the starting compounds. The crystal structures of the MnGaInTe 4 and MnIn 2 Tе 4 were refined by the Rietveld method using powder X-ray diffraction data. It was established, that both phases crystallize in the tetragonal system (Space group I-42m). Electron paramagnetic resonance and Raman spectra, as well as the temperature dependences of the electrical conductivity and the Hall effect for the MnGaInTe 4 crystal, were studied.

No abstract