  Electronic states with non-trivial topology host a number of novel phenomena
with potential for revolutionizing information technology. The quantum
anomalous Hall effect provides spin-polarized dissipation-free transport of
electrons, while the quantum spin Hall effect in combination with
superconductivity has been proposed as the basis for realizing decoherence-free
quantum computing. We introduce a new strategy for realizing these effects,
namely by hole and electron doping kagome lattice Mott insulators through, for
instance, chemical substitution. As an example, we apply this new approach to
the natural mineral herbertsmithite. We prove the feasibility of the proposed
modifications by performing ab-initio density functional theory calculations
and demonstrate the occurrence of the predicted effects using realistic models.
Our results herald a new family of quantum anomalous Hall and quantum spin Hall
insulators at affordable energy/temperature scales based on kagome lattices of
transition metal ions.
