Intercalation-enhanced topological material Bi2Se3: Tuning charge carrier and phonon dynamics for advanced optoelectronic and terahertz applications

The field of topological materials (TMs) is experiencing significant advancements due to their unique surface states, which offer considerable potential for optoelectronics and terahertz (THz) applications. Intercalation in TMs can effectively modulate these surface states, thereby altering electronic and optical properties and enhancing functionalities. This approach enables the tailoring of material properties for specific applications, broadening the utility of TMs across various technological domains. This study focuses on understanding the charge carrier and phonon dynamics in bismuth selenide (BiSe) intercalated with various metals (ABiSe, where A = Ag, Cr, Ni, Mn, Sm, Zn). We examine carrier trapping, carrier relaxation through optical and acoustic phonons, charge recombination processes, and variations in carrier temperature with probe delay lifetimes. Additionally, we explore coherent optical phonons (COPs) in MIBS, which oscillate at THz frequencies and have potential applications in THz generation and detection. Achieving tunability in the THz frequency of COP modes is a significant challenge; however, our research establishes a correlation between optical and structural properties and the dependence of COP frequencies on effective metal intercalation. This comprehensive investigation elucidates the intricate interplay between surface carriers and phonon dynamics in intercalated TMs, highlighting promising advancements for diverse technological applications, including spintronics, optoelectronics, and THz technology.