Cesium migration and equilibrium in a strong electric field on the surface of silicon

It is found experimentally that a balance between the chemical force and the force due to an applied electric field acting on fractionally charged cesium particles on the surface of silicon leads to an equilibrium state. Measurements of the coverage gradient (∂θ/∂x) in this equilibrium state give a relation between the gradient of the chemical potential (mainly the binding energy Ub) and the fractional charge of the cesium particles. For cesium atoms on silicon this relation is found to be f=0.16∂Ub/∂θ+0.03.