Co-tunneling current through the two-level quantum dot coupled to magnetic leads: A role of exchange interaction

TL;DR

This paper investigates the co-tunneling current in a two-level quantum dot with ferromagnetic leads, revealing how magnetic configurations and exchange interactions influence conductance and interference effects.

Contribution

It provides a detailed analysis of elastic and inelastic co-tunneling processes, highlighting the role of exchange interaction and phase dependence in the current behavior.

Findings

Differential conductance shows staircase structure varying with magnetic alignment.

Elastic and inelastic processes contribute distinctly to the co-tunneling current.

Interference effects depend on the phases of tunneling amplitudes.

Abstract

The co-tunneling current through a two-level doubly occupied quantum dot weakly coupled to ferromagnetic leads is calculated in the Coulomb blockade regime. It is shown that the dependence of the differrential conductance on applied voltage has a stair-case structure with different sets of "stairs" for parallel and anti-parallel configurations of magnetization of the leads. Contributions to the current from elastic and inelastic processes are considered distinctly. It is observed that the interference part of the co-tunneling current involves terms corresponding to inelastic processes. Dependence of the co-tunneling current on the phases of the tunneling amplitudes is studied.