Correlation of the optical and magnetic properties of Bi$_{2}$Te$_{3}$–Sb$_{2}$Te$_{3}$ crystals

During the study of Bi$_{2}$Te$_{3}$–Sb$_{2}$Te$_{3}$ crystals, their magnetic and optical properties were studied depending on the ratios of the components of Bi$_{2}$Te$_{3}$ and Sb$_{2}$Te$_{3}$ in the composition of the solid solution and temperature. The results obtained allow us to state that a sharp decrease in the anisotropy of magnetic susceptibility at $T$ = 293 K is observed in those samples in which, according to optical studies, electron-plasmon interaction is intensified, which is caused by the convergence of plasmon energies and interband transitions that form the fundamental absorption edge.