The movement of charge carriers in a metal or semiconductor under the influence of an electric field. The resulting average velocity of the charge carriers is known as the drift velocity, v, which is linearly related to the electric field by the parameter drift mobility, μ:

The drift current, J, is then the product of the carrier charge density and their average velocity:

which is an expression of Ohm’s law. The parameter neμ is the conductivity of the material.