Universal electric current of interacting resonant-level models with asymmetric interactions: An extension of the Landauer formula

TL;DR

This paper extends the Landauer formula to interacting resonant-level models with asymmetric couplings, deriving a universal electric current that exhibits negative differential conductance and can be restored by system asymmetry.

Contribution

It provides an exact construction of scattering states and an extension of the Landauer formula for asymmetric interacting quantum-dot systems, revealing universal current behavior.

Findings

Universal electric current with negative differential conductance

Current suppression and restoration via system asymmetry

Exact scattering eigenstates for asymmetric interactions

Abstract

We study the electron transport in open quantum-dot systems described by the interacting resonant-level models with Coulomb interactions. We consider the situation in which the quantum dot is connected to the left and right leads asymmetrically. We exactly construct many-electron scattering eigenstates for the two-lead system, where two-body bound states appear as a consequence of one-body resonances and the Coulomb interactions. By using an extension of the Landauer formula, we calculate the average electric current for the system under bias voltages in the first order of the interaction parameters. Through a renormalization-group technique, we arrive at the universal electric current, where we observe the suppression of the electric current for large bias voltages, i.e., negative differential conductance. We find that the suppressed electric current is restored by the asymmetry of the system parameters.