Electron Cotunneling into a Kondo Lattice

Motivated by recent experimental interest in tunneling into heavy-electron materials, we present a theory for electron tunneling into a Kondo lattice. The passage of an electron into a Kondo lattice is accompanied by a simultaneous spin flip of the localized moments via cotunneling mechanism. We compute the tunneling current with the large-N mean field theory. In the absence of disorder, differential tunneling conductance exhibits two peaks separated by the hybridization gap. Disorder effects lead to the smearing of the gap resulting in a Fano line shape.