RELATIONSHIP BETWEEN PHASE-SHIFT AND ENERGY-DISSIPATION IN TAPPING-MODE SCANNING FORCE MICROSCOPY

Force curves taken during a load-unload cycle show the presence of a h ysteresis loop. The area enclosed by the loop is used to measure the e nergy dissipated by the tip-sample interaction in tapping-mode scannin g force microscopy. The values of the energy loss obtained from force curves are compared with the results derived from a model based on pha se shift measurements. The agreement obtained between both methods dem onstrates that for the same operating conditions, the higher the phase shift the larger the amount of energy dissipated by the tip-sample in teraction. It also confirms the prediction that phase-contrast images can only arise if there are tip-sample inelastic interactions. (C) 199 8 American Institute of Physics. [S0003-6951(98)03646-8].