Experiments and theoretical calculations of conservative forces measured by frequency
modulation atomic force microscopy (FM-AFM) in vacuum are generally in reasonable
agreement. This contrasts with dissipative forces, where experiment and theory often
disagree by several orders of magnitude. These discrepancies have repeatedly been
attributed to instrumental artifacts, the cause of which remains elusive. We demonstrate that
the frequency response of the piezoacoustic cantilever excitation system, traditionally …

Frequency modulation atomic force microscopy (FM-AFM) utilizes the principle of self-
excitation to ensure the cantilever probe vibrates at its resonant frequency, regardless of the
tip-sample interaction. Practically, this is achieved by fixing the phase difference between tip
deflection and driving force at precisely 90°. This, in turn, decouples the frequency shift and
excitation amplitude signals, enabling quantitative interpretation in terms of conservative
and dissipative tip-sample interaction forces. In this article, we theoretically investigate the …