Signatures of the Correlated‐Hopping Interaction in Non‐Linear Transport Through a Quantum Dot

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 in the non‐linear regime , is a prerequisite for its experimental detection. In this paper, the non‐linear transport properties of junctions composed of a quantum dot tunnel coupled to external electrodes are studied. The system is modeled 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, relevant transport characteristics are calculated in the strongly non‐linear regime.