Please explain what the coulomb blockage effect in nanoscale

Please explain what the coulomb blockage effect in nanoscale material is.

Solution

In physics, a Coulomb blockade (CB), named after Charles-Augustin de Coulomb\'s electrical force, is the increased resistance at smallbias voltages of an electronic device comprising at least one low-capacitance tunnel junction. Because of the CB, the resistances of devices are not constant at low bias voltages, but increase to infinity for biases under a certain threshold (i.e. no current flows). When few electrons are involved and an external static magnetic field is applied, Coulomb blockade provides the ground for spin blockade (also called Pauli blockade) and valley blockade which includes quantum mechanical effects due to spin and orbital interactions respectively between the electrons.

Coulomb blockade will also be observed when making the device very small (Like quantum dot). When the device is small enough, electrons inside the device will create a strong coulomb repulsion prevent other electron moving in. The device will no longer follow ohm\'s law. The current-voltage relation of coulomb blockade looks like a staircase.