Method for determining a spring constant for a deformable scanning probe microscope element, and scanning probe microscope and calibration device arranged for determing a spring constant for a probe element

A method for determining a spring constant k for a deformable probe element (102) of a scanning probe microscope SPM (100). The probe (102) has an outer surface area consisting of a tip area (112) on a first probe side (108) and a tip-less area (113). The probe (102) also has a probe electrode (114) and a scanning probe tip (104) in the tip area (112). The method comprises: providing an actuation electrode (116) that is spatially separated from the probe (102); adjusting a potential difference V applied between the probe electrode (114) and the actuation electrode (116); deflecting the probe (102) into a contacted state of the actuation electrode (116) with only a contact portion (115) of the tip-less probe area (113); measuring an EPI-potential difference Vpi between probe electrode (114) and actuation electrode (116), and deriving the spring constant k, based on the EPI-potential difference Vpi. Furthermore, an SPM (100) and calibration device (200) with this method functionality are provided.