Exotic odd-even parity effects in transmission phase, (Andreev) conductance, and shot noise of a dimer atomic chain by topology

摘要

We investigate the transport properties through a finite dimer chainconnected to two normal leads or one normal and one superconductor (SC) leads.The dimer chain is described by the Su-Schrieffer-Hegger model and can be tunedinto a topologically nontrivial phase with a pair of zero-energy edge states(ZEESs). We find that if the dimer chain is of nontrivial topology, (1) it willshow apparent but opposite odd-even parity of the number of sites, incomparison with the topologically trivial and plain chains, in the (Andreev)transmission probability at the Fermi energy (i.e. the conductance and theAndreev conductance), the noise Fano factor in the zero bias limit, and eventhe transmission phase due to the coupled ZEESs; (2) the ZEES can determineappearance of the Andreev bound states at the site connected to the SC lead,and thereby induces a nonzero-bias-anomaly in the Andreev differentialconductance of the hybrid junction; (3) the transmission phase of the normaljunction has a unique $2\pi$ continuous phase variation at the zero-energyresonant peak that is also different from the usual phase shift in resonantpoint in usual systems.