Anderson impurity in the bulk of topological insulators

When an Anderson impurity is immersed in the bulk of a topological insulator that has an "inverted-Mexican-hat" band dispersion, a Kondo resonant peak appears simultaneously with an in-gap bound state. The latter generates another spin state thereby screening the Kondo effect. Using a weak-coupling RG scheme, it is shown that the system exhibits complex crossover behavior between different symmetry configurations and may evolve into a self-screened Kondo or an SO(n)(n=3,4) low-energy fixed point. Experimental consequences of these scenarios are pointed out.