This article is cited in 3 papers

Nonequilibrium Green's functions in the atomic representation and the problem of quantum transport of electrons through systems with internal degrees of freedom

V. V. Val'kov, S. V. Aksenov

Kirensky Institute of Physics, Siberian Branch, RAS, Krasnoyarsk, Russia

Abstract: We develop the theory of quantum transport of electrons through systems with strong correlations between fermionic and internal spin degrees of freedom. The atomic representation for the Hamiltonian of a device and nonequilibrium Green's functions constructed using the Hubbard operators allow overcoming difficulties in the perturbation theory encountered in the traditional approach because of a larger number of bare scattering amplitudes. Representing the matrix elements of effective interactions as a superposition of terms each of which is split in matrix indices, we obtain a simple method for solving systems of very many equations for nonequilibrium Green's functions in the atomic representation. As a result, we obtain an expression describing the electron currents in a device one of whose sites is in tunnel coupling with the left contact and the other, with the right contact. We derive closed kinetic equations for the occupation numbers under conditions where the electron flow leads to significant renormalization of them.

Keywords: nonequilibrium Green's functions, Keldysh contour, atomic representation, kinetic equation, inelastic scattering.

Received: 02.05.2017
Revised: 22.05.2017

DOI: 10.4213/tmf9396

 English version: Theoretical and Mathematical Physics, 2018, 194:2, 236–251

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