Investigation of dynamic optical study of Bi2Te3 topological insulators thin film based on MWCNT flexible paper using terahertz spectroscopy

Abstract The massless Dirac electron shows a linear energy dispersion in topological insulators (TIs) and these materials posses interesting properties such as high mobility, tuneable density and protection against backscattering over the time reversal symmetry and strong spin-orbit interaction. The flexibility is also an important parameter for development of wearable devices specially THz detector for imaging and quantum devices for optoelectronics applications. In this research work first time Bi2Te3 TIs thin film is fabricated on inhouse develop metallic multi wall carbon nanotubes flexible paper (MWCNT-FP) and characterized by terahertz-time domain spectroscopy acquired at room temperature. This research work delivers exclusive opportunities to explore interesting phenomena in topological surface states and topological phase transition in Bi2Te3 TIs thin film. Here, we measured terahertz absorption, optical density conductance and conductivity. An excellent broad band absorption is observed between 0.02 and 3.0 THz. The real conductance level is scientifically quite linear below 3.0 meV and thereafter certain increase. Similar trend is observed for the study of an imaginary conductance with respect to photon energy. The optical conductivity is observed in the range of 0.02–2.0 THz.