Temperature dependence of the energy dissipation in dynamic force microscopy

TL;DR

This study investigates how energy dissipation in dynamic force microscopy varies with temperature on PTCDA and KBr surfaces, revealing different behaviors that suggest multiple underlying dissipation mechanisms.

Contribution

It provides experimental data on temperature-dependent energy dissipation in DFM, highlighting a discrepancy with existing models and suggesting new mechanisms for KBr.

Findings

Dissipation decreases with temperature on PTCDA, consistent with adhesion hysteresis.

Dissipation increases with temperature on KBr, indicating a different mechanism.

Energy dissipation values at room temperature are 1.9 eV/cycle for PTCDA and 2.7 eV/cycle for KBr.

Abstract

The dissipation of energy in dynamic force microscopy is usually described in terms of an adhesion hysteresis mechanism. This mechanism should become less efficient with increasing temperature. To verify this prediction we have measured topography and dissipation data with dynamic force microscopy in the temperature range from 100 K up to 300 K. We used 3,4,9,10-perylenetetracarboxylic-dianhydride (PTCDA) grown on KBr(001), both materials exhibiting a strong dissipation signal at large frequency shifts. At room temperature, the energy dissipated into the sample (or tip) is 1.9 eV/cycle for PTCDA and 2.7 eV/cycle for KBr, respectively, and is in good agreement with an adhesion hysteresis mechanism. The energy dissipation over the PTCDA surface decreases with increasing temperature yielding a negative temperature coefficient. For the KBr substrate, we find the opposite behaviour: an increase of dissipated energy with increasing temperature. While the negative temperature coefficient in case of PTCDA agrees rather well with the adhesion hysteresis model, the positive slope found for KBr points to a hitherto unknown dissipation mechanism.