Highly asymmetric atom-lead coupling in nanowires for resonance regime

Concerning quantum transport at resonant states in a one-atom nanowire (nanoconstriction), for the first time, a theoretical study is presented upon strongly asymmetric coupling between the atom at the nanoconstriction and the involved leads. Under these conditions, an approximate relationship for the conductance at resonance in a single-atom wire is considered and an expression for the number of resonant states is derived and discussed. In addition, the density of resonant electronic states is determined under a quantum-box approach by which the conduction electrons are assumed to behave as quantum harmonic oscillators confined in a potential well transverse to the wire.