Universal conductance enhancement and reduction of the two-orbital Kondo effect

TL;DR

This paper theoretically examines how interaction asymmetry influences conductance in two-orbital Kondo systems, revealing conductance enhancement or reduction and suggesting SU(4) universal behavior consistent with experiments.

Contribution

It introduces a theoretical analysis of conductance modulation due to interaction asymmetry in two-orbital Kondo systems, highlighting effects on linear and nonlinear conductance profiles.

Findings

Interaction asymmetry significantly alters conductance profiles.

SU(4) universal behavior is observed within feasible experimental parameters.

Comparison with experiments supports the theoretical predictions.

Abstract

We investigate theoretically the linear and nonlinear conductance through a nanostructure with two-fold degenerate single levels, corresponding to the transport through nanostructures such as a carbon nanotube, or double dot systems with capacitive interaction. It is shown that the presence of the interaction asymmetry between orbits/dots affects significantly the profile of the linear conductance at finite temperature, and, of the nonlinear conductance, particularly around half-filling, where the two-particle Kondo effect occurs. Within the range of experimentally feasible parameters, the SU(4) universal behavior is suggested, and comparison with relevant experiments is made.