Intrinsic quasi-particle dynamics of topological metallic states

We investigate the intrinsic quasi-particle (QP) dynamics in the topological metallic (TM) states of Bi2Se3, Bi2-xSnxTe3 (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 Sigma for the QPs in the TM states. We attribute the binding energy-independent Im Sigma 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 Sigma for QPs. Our new observations on the extremely small intrinsic QP scattering rates may open up the possibility of room-temperature quantum devices.