Skip to main content

Atomic Force Microscopy

Work of adhesion between the the AFM tip and the surface of a polymer blend sample (PolyStyrene-PolyCapralactone).

We analyze the nonlinear oscillations  of an AFM cantilever to reveal the forces between the tip and the surface. The cantilever is driven with two pure tones and the nonlinear tip-surface force gives rise to frequency mixing, or intermodulation  of the drive tones. Here is a link to a movie  which demonstrates intermodulation as the AFM probe approaches a surface. With a multifrequency intermodulation lockin we capture in real-time the amplitude and phase at many intermodulation products as we scan. The method gives multiple amplitude and phase images in one scan, with each image showing rich and varying contrast. We have several different algorithms for interpreting the intermodulation spectra at each image pixel in terms of the conservative and dissipative forces between the tip and surface. We have also developed multifrequency methods to quickly extract current-voltage characteristics in conducting AFM and STM.

Find our recent publications at this link . You can also find further information on the website of Intermoduation Products .

We are coordinating an EU project Q-AFM , part of the FET-Open  program, with the goal of developing the next generation of quantum-limited resonant mechanical force sensors for the low-temperatute AFM community.

Links to PhD Theses: Erik Tholén 2009 , Daniel Platz 2013 , Daniel Forchheimer 2015 , Per Anders Thorén 2018 , Riccardo Borgani 2018 .

Page responsible:David B Haviland
Belongs to: Nanostructure Physics
Last changed: Apr 26, 2019