Kondo Breakdown in Topological Kondo Insulators

Motivated by the observation of light surface states of SmB$_6$, we examine the effects of surface Kondo breakdown in topological Kondo insulators. We present both numerical and analytic results which show that the decoupling of the localized moments at the surface disturbs the compensation between light and heavy electrons and dopes the Dirac cone. Dispersion of these uncompensated surface states are dominated by inter-site hopping, which leads to a much lighter quasiparticles. These surface states are also highly durable against effects of magnetism and decreasing the thickness of the sample.