The relationship between the plasma edge and topological properties of Sb₂Te₃ under pressure

Topological insulators have garnered considerable attention in recent years due to their unique electronic properties. However, pressure-induced topological materials often located in the middle of the two diamonds and cannot be detected by Angle resolved electron spectra. Such topological materials only stay in theoretical calculated. Since diamond has a high optical transmittance, its optical properties have been extensively studied to probe the band structure of topological insulators under pressure. In this paper, we determine the highpressure infrared (IR) properties by measuring the transmittivity and reflectivity of Sb2Te3 up to 23.2 GPa. The plasma edge shows jumping at 4.2 GPa and 8.5 GPa, where is caused by the change of charge carrier features and a new phase appears at 8.5 GPa. Furthermore, by analyzing the position of plasma edge under pressure, we find that the absence of plasma edge at high pressure corresponds to the disappearance of the Sb2Te3 topological structure. Therefore, utilizing the plasma edge to investigate the modification of band structure in materials under high pressures is highly effective.