Ангармонизм колебаний кристаллической решетки монокристаллов Bi-=SUB=-2-=/SUB=-Se-=SUB=-3-=/SUB=-

Abstract

The temperature dependences of the Raman-active frequencies $$E_{g}^{2}$$ , $$A_{{1g}}^{2}$$ in layered Bi_2Se_3 single crystals are studied. The contribution of the thermal expansion to a temperature variation in the frequencies is determined. The decay of the anisotropy of the elastic properties in layered Bi_2Se_3 single crystals due to strong spin–orbit coupling is shown. The Gruneisen-mode parameters for phonons $$E_{g}^{2}$$ and $$A_{{1g}}^{2}$$ are calculated. Systematic features in the dependences of vibrational frequencies on the atomic masses in layered Bi_2Te_3, Bi_2Se_3, and Sb_2Te_3 single crystals are determined.