magnetic topological insulator*

MnBi₂Te₄, made by intercalating a Mn-Te layer into a topological insulator Bi₂Te₃, is an antiferromagnetic topological insulator of abundant research potential due to its exotic physical properties—quantum anomalous Hall effect, Axion insulator, and Dirac semimetal depending on the magnetic state and its directions. Especially, the layered structure of MnBi₂Te₄ allows for the exhibition of many turntable capabilities, making it a valuable platform in device applications. In this article, we use Raman spectroscopy, which provides us with a structural fingerprint of the material, under various polarization and temperature dependent configurations to study the phonon modes of (100) direction of bulk MnBi₂Te₄. We observed intensity differences at 46, 113, and 146 cm^-1 peaks between the right and left cross circular polarization configurations while they had the same intensity in co-circular polarization. In addition, A-axis MnBi₂Te₄ had rotation anisotropic polarization Raman spectra, with a 6-degree rotation when comparing above and below the transition temperature of MnBi₂Te₄. Our results contribute to understanding the phonon modes of (100) direction MnBi₂Te₄, and paves the way to tailoring its properties for use in promising emerging applications.