Negative Conductance in Coulomb Blockade

概要

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Based on the Anderson model with nonequilibrium distribution, we discuss the current between two electrodes through an atom with a finite bias voltage. The Anderson model is used to study the Coulomb blockade phenomenon from the small system size limit. We employ the Mahanthappa-Baksi-Keldysh Green function formalism to deal with the nonequilibrium system. The second-order perturbation study with respect to the Coulomb interaction between electrons in the atomic orbital is performed by starting with the restricted Hartree-Fock solution. We show results of various cases of the relative position of energy level on the atom with respect to the Fermi energies in two electrodes. Several behaviors of the conductance, such as the Kondo-assisted tunneling and blocking of the current by the Coulomb repulsion, are found. It is also shown that the conductance can be negative under special conditions. We discuss the physical nature of these effects in terms of the local density of states on the atom.
社団法人応用物理学会の論文
1996-06-30