Basel Universität

Pendulum UHV-AFM

Pendulum UHV-AFM is an unique design dedicated to the measurement of extremely small forces in order of aN. In the pendulum geometry the cantilever is hoovering perpendicularly to the sample surface, shearing the nanometer vacuum gap between tip and the sample. In this arrangement very soft cantilevers with spring constants of k≈10-5 - 10-3 N/m can be used as force sensors, avoiding snapping into the contact with the sample. The force sensitivity Fmin is then:

Pendulum AFM operates at cryogenic temperatures (T=5K) and typical quality factors are in the order of Q≈105 - 106. Such high Q together with extremely small k (both at the limit for silicon cantilevers) imply that minimal detectable energy dissipation:

is few orders of magnitude smaller as compared to standard AFM configuration.

Those tiny amount of dissipation (non-contact friction) is successfully measured by means of pendulum AFM. The studies of nanoscale non-contact friction over phase transitions in solids are major scientific activity.
The instrument is mounted in the UHV system and measurements are carried out on atomically clean samples. The preparation and exchanging of the cantilevers and samples are done under UHV conditions. The microscope can be operated in a variable temperature range of 4-300K with the presence of external magnetic field (±7 T). In addition to AFM, the microscope is also furnished with the Scanning Tunneling (STM) line.

Publications related to this instrument:

Intricacies Of Moiré Patterns At The Atomic Level: A Scanning Probe Microscopy Perspective
D. Yildiz, M. Kisiel, O. Gurlu, and E. Meyer
Ecotrib2015, 2015-06-25, Lugano, (Switzerland).
Investigation Of Morphological And Electronic Properties Of Moiré Patterns By Scanning Probe Microscopy
D. Yildiz, M. Kisiel, O. Gurlu, and E. Meyer
The International Conference on Understanding and Controlling Nano and Mesoscale Friction, 2015-06-24, Istanbul, (Turkey).
Investigation Of Morphological And Electronic Properties Of Moiré Patterns By Scanning Probe Microscopy
D. Yildiz, M. Kisiel, O. Gurlu, and E. Meyer
Swiss Nano Convention 2015, 2015-05-27, Neuchâtel, (Switzerland).
Scanning Probe Microscopy (SPM) study of moiré patterns on rotated graphene layer on Highly Oriented Pyrolytic Graphite (HOPG)
D. Yildiz , S. Sen, M. Kisiel, O. Gulseren, E. Meyer, and O. Gurlu
DPG Spring Meeting, 2015-03-19, Berlin, (Germany).
Noncontact Atomic Force Microscope Dissipation Reveals a Central Peak of SrTiO3 Structural Phase Transition
M. Kisiel, F. Pellegrini, G. E. Santoro, M. Samadashvili, R. Pawlak, A. Benassi, U. Gysin, R. Buzio, A. Gerbi, E. Meyer, & E. Tosatti
Phys. Rev. Lett., 115, (2015), 046101, pdf.
Dissipation at large separation (Ed. E. Gnecco and E. Meyer)
M. Kisiel, M. Langer, U. Gysin, S. Rast, E. Meyer, D.W. Lee
Fundamentals of Friction and Wear on the Nanoscale (Edited b, Vol. 2, (Chap. 26), (2015), 609-626, pdf.
Non-contact friction
M. Kisiel, M. Samadashvili, U. Gysin, E. Meyer
Noncontact Atomic Force Microscopy (Edited by S. Morita, F.J, Vol.3, (2015), 93-110, pdf.
Giant frictional dissipation peaks and charge-density-wave slips at the NbSe2 surface
M. Langer, M. Kisiel, R. Pawlak, F. Pelligrini, G. E. Santoro, R. Buzio, A. Gerbi, G. Balakrishnan, A. Baratoff, E. Tosatti, E. Meyer
Nature Materials, 13, (2014), 173-177, pdf.
Suppression of electronic friction on Nb films in the superconducting state
M. Kisiel, E. Gnecco, U. Gysin, L. Marot, S. Rast, E. Meyer
Nature Materials, 10, (1), (2011), pdf.
Low temperature ultrahigh vacuum noncontact atomic force microscope in the pendulum geometry
U. Gysin, S. Rast, M. Kisiel, C. Werle, and E. Meyer
Rev. Sci. Instrum., 82, (2011), 023705, pdf.