Coulomb blockade: Poisson versus Pauli in a silicon quantum box

We discuss the limitations of the orthodox Coulomb-blockade theory when applied to silicon quantum dots in the nanometer range and we present a simple Poisson-Schrodinger model to evaluate the quantum contribution in these cases. This contribution can be seen as a quantum capacitance in series with the sum of capacitance around the dot. This simple model gives results similar to a more sophisticated one which includes Pauli principle, with a precision of the order of room-temperature thermal-energy kT. Finally we show that the simple model can be easily included in micro-electronic simulators and therefore can be very effective to predict new properties of future quantum devices. All the effects discussed in this paper are room-temperature effects.