Temperature Studies of Raman Spectra in MnBi2Te4 and MnSb2Te4 Magnetic Topological Insulators

Raman spectra of magnetic topological crystalline insulators in a wide temperature range including the magnetic ordering region are studied in detail. The anharmonicity parameters and Grüneisen mode parameters of Raman-active phonons in the studied crystals have been determined. It has been shown that the temperature dependence of the frequency of the \(A_{{{\text{1g}}}}^{{(1)}}\) (~48 cm^–1) phonon in MnBi₂Te₄ coincides within ±0.1 cm^–1 with the standard anharmonic model disregarding the spin–phonon coupling. The polarization dependences of Raman spectra in the MnSb₂Te₄ crystals indicate that Sb and Mn atoms are strongly mixed in them unlike the isostructural MnBi₂Te₄ crystals.