Nonlinear Fermi-liquid transport through a quantum dot in asymmetric tunnel junctions

Abstract

We study the nonlinear conductance through a quantum dot, specifically its dependence on the asymmetries in the tunnel couplings and bias voltages $V$, at low energies. Extending the microscopic Fermi-liquid theory for the Anderson impurity model, we obtain an exact formula for the steady current $I$ up to terms of order $V^3$ in the presence of these asymmetries. The coefficients for the nonlinear terms are described in terms of a set of the Fermi-liquid parameters: the phase shift, static susceptibilities, and three-body correlation functions of electrons in the quantum dots, defined with respect to the equilibrium ground state. We calculate these correlation functions, using the numerical renormalization group approach (NRG), over a wide range of impurity-electron filling that can be controlled by a gate voltage in real systems. The NRG results show that the order $V^2$ nonlinear current is enhanced significantly in the valence fluctuation regime. It is caused by the order $V$ energy shift of the impurity level, induced in the presence of the tunneling or bias asymmetry. Furthermore, in the valence fluctuation regime, we also find that the order $V^3$ nonlinear current exhibits a shoulder structure, for which the three-body correlations that evolve for large asymmetries play an essential role.

18 pages, 27 figures. Typos have been corrected

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• Role of bias and tunneling asymmetries in nonlinear Fermi-liquid transport through an SU($N$) quantum dot
• Thermoelectric transport and current noise through a multilevel Anderson impurity: Three-body Fermi-liquid corrections in quantum dots and magnetic alloys
• Kondo Temperature Evaluated from Linear Conductance in Magnetic Fields
• Transport in Single Quantum Dots: A Review from Linear Response to Nonlinear Regimes
• Three-body Fermi liquid corrections for an infinite-$U$ SU($N$) Anderson impurity model
• Three-body Fermi-liquid corrections for Andreev transport through quantum dots