The effect of patch potentials in Casimir force measurements determined by heterodyne Kelvin probe force microscopy

Abstract

Measurements of the Casimir force require the elimination of electrostatic interactions between the surfaces. However, due to electrostatic patch potentials, the voltage required to minimize the total force may not be sufficient to completely nullify the electrostatic interaction. Thus, these surface potential variations cause an additional force, which can obscure the Casimir force signal. In this paper, we inspect the spatially varying surface potential (SP) of e-beamed, sputtered, sputtered and annealed, and template stripped gold surfaces with Heterodyne Amplitude Modulated Kelvin Probe Force Microscopy (HAM-KPFM). It is demonstrated that HAM-KPFM improves the spatial resolution of surface potential measurements compared to Amplitude Modulated Kelvin Probe Force Microscopy (AM-KPFM). We find that patch potentials vary depending on sample preparation, and that the calculated pressure can be similar to the pressure difference between Casimir force calculations employing the plasma and Drude models.

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Cited by in corpus (5)

• Comparison of Casimir forces and electrostatics from conductive SiC-Si/C and Ru surfaces
• Electrostatic effect due to patch potentials between closely spaced surfaces
• Dependence of Electrostatic Patch Force Evaluation on the Lateral Resolution of Kelvin Probe Force Microscopy
• Nanoscale electrical measurements in liquids using AFM - progress and outlook
• Atom-surface interaction induced by quenched monopolar charge disorder