Intrinsic quasi-particle dynamics of topological metallic states

We investigate the intrinsic quasi-particle (QP) dynamics in the topological metallic (TM) states of Bi 2 Se 3 , Bi 2− x Sn x Te 3 ( x =0.0067) and Sb. Surprisingly, the intrinsic QP dynamics are mostly determined by the scattering within the TM states and are unaffected by the bulk electronic states. We observe the binding energy-independent imaginary part of the self-energy Im Σ for the QPs in the TM states. We attribute the binding energy-independent Im Σ to momentum mixing due to flakes or warped surfaces of the cleaved samples. This makes the intrinsic scattering rate of the QPs extremely small in the TM states. We discuss a few possible contributions to the smallness of the Im Σ for QPs. Our new observations on the extremely small intrinsic QP scattering rates may open up the possibility of room-temperature quantum devices.