From the Coulomb blockade regime to the Non-Coulomb blockade regime

The investigations on the Coulomb blockade (CB) effect, which strongly affects the transport properties of the quantum devices, are generally restricted to the regime where the Coulomb repulsion U is far larger than the temperature T, yet the critical status was not discussed. We represent the boundary between the CB and Non-CB regimes with the nonequilibrium Green's function approach based on the equation of motion by employing a quantum dot model. The boundary line can be expressed with a equation Γ/U=f(T/U), and then the systems will be in CB regime when Γ/U<f(T/U). Thus, this boundary allows us to easily know when the CB effect is significant in the electronic device investigations