Impurity-modulated ultrafast carrier dynamics in 3D Dirac semimetal Cd3As2

In this work, we use optical pump-terahertz (THz) probe spectroscopy to investigated the impurity-induced topological phase transition and the photo-induced carrier behavior in cadmium arsenide (Cd3As2), a three-dimensional Dirac semimetal. By comparing the dynamics of different temperature and pump fluence, we discuss the carrier dynamics and physical mechanism caused by impurity.