Kelvin probe force microscopy of metallic surfaces used in Casimir force measurements

摘要

Kelvin probe force microscopy at normal pressure was performed by twodifferent groups on the same Au-coated planar sample used to measure theCasimir interaction in a sphere-plane geometry. The obtained voltagedistribution was used to calculate the separation dependence of theelectrostatic pressure $P_{\rm res}(D)$ in the configuration of the Casimirexperiments. In the calculation it was assumed that the potential distributionin the sphere has the same statistical properties as the measured one, and thatthere are no correlation effects on the potential distributions due to thepresence of the other surface. Within this framework, and assuming that thepotential distribution does not vary significantly at low pressure, thecalculated $P_{\rm res}(D)$ does not explain the magnitude or the separationdependence of the difference $\Delta P (D)$ between the measured Casimirpressure and the one calculated using a Drude model for the electromagneticresponse of Au.