Superradiant and transport lifetimes of the cyclotron resonance in the topological insulator HgTe

We investigate the superradiance effects in three-dimensional topological insulator HgTe with conducting surface states. We demonstrate that the superradiance can be explained using the classical electrodynamic approach. Experiments using the continuous-wave spectroscopy allowed us to separate the energy losses in the system into intrinsic and radiation losses, respectively. These results demonstrate that the superradiance effects are not sensitive to the details of the band structure of the material.