Patent ID: 7861577

Claim:
An electric potential difference detection method for detecting an electric potential difference between a surface of a sample and a probe of a cantilever using a scanning probe microscope comprising the cantilever and a sample base mounting the sample so as to confront the probe of the cantilever, the method comprising: a voltage application step that applies, between the surface of the sample and the cantilever, an AC voltage having a frequency that is Â½ of a resonance frequency of the cantilever; a detection step that detects a magnitude of an amplitude of the cantilever following the voltage application step; and an analysis step that judges, on the basis of the detected vibration characteristics of the cantilever, an existence of an electric potential difference between the surface of the sample and the probe of the cantilever in a case where the cantilever is not resonating and the detected magnitude of the amplitude of the cantilever is smaller than a predetermined magnitude.