Probing zero-modes of defect in Kitaev quantum wire

摘要

The Kitaev quantum wire (KQW) model with open boundary possesses two Majoranaedge modes. When the local chemical potential on a defect site is much higherthan that on other sites and than the hopping energy, the electron hopping isblocked at this site. We show that the existence of such a defect on a closedKQW also gives rise to two low-energy modes, which can simulate the edge modes.The energies of the defect modes vanish to zero as the local chemical potentialof the defect increase to infinity. We develop a quantum Langevin equation tostudy the transport of KQW for both open and closed cases. We find that whenthe lead is contacted with the site beside the defect, we can observe twosplitted peaks around the zero-bias voltage in the differential conductancespectrum. While if the lead is contacted with the bulk of the quantum wire farfrom the the defect or the open edges, we cannot observe any zero-bias peak.