Signatures of the Correlated-Hopping Interaction in Non-Linear Transport through a Quantum Dot

TL;DR

This paper investigates how correlated-hopping interactions influence non-linear transport in quantum dot systems, revealing signatures that could enable experimental detection of these non-local effects beyond linear response.

Contribution

It introduces a detailed analysis of correlated-hopping effects on non-linear transport in quantum dots using an extended Anderson model, highlighting their impact on measurable characteristics.

Findings

Correlated-hopping breaks particle-hole symmetry in quantum dots.

Non-linear transport characteristics are significantly affected by correlated-hopping.

Results provide potential signatures for experimental detection of correlated-hopping effects.

Abstract

In condensed matter systems with the Coulomb interaction playing an important role one expects, besides the on-site (local) Hubbard-type interaction, that also other (non-local) terms depending on the site occupancy, known as correlated or assisted hopping, exist. Even though such terms in quantum dots tunnel coupled to external electrodes may have quite an appreciable amplitude, the interpretation of experiments on these systems -- usually in the linear response regime -- seems not to require their presence. However, since the correlated-hopping term breaks the particle-hole symmetry of the standard Anderson model and modifies all transport characteristics of the system, the detailed knowledge of its influence on measurable characteristics, especially {\em in the non-linear regime}, is a prerequisite for its experimental detection. In this paper, we study the non-linear transport properties of junctions composed of a quantum dot tunnel coupled to external electrodes. We model the system by the single-impurity Anderson Hamiltonian with Hubbard on-site interaction and with a non-local correlated-hopping interaction. Using the previously found general expression for the spin-dependent transport and spectral Green functions as well as general formulae for charge and heat transport, we calculate relevant transport characteristics in the strongly non-linear regime