Noncontact Friction in Electric Force Microscopy over a Conductor with Nonlocal Dielectric Response
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States.
The Journal of Physical Chemistry. A
|September 6, 2022
Summary
This study calculates noncontact friction over bare metal surfaces using a wavevector-dependent dielectric function. Results show this approach enhances friction and alters its dependence on tip-sample separation compared to continuum models.
Area of Science:
- Physics
- Materials Science
- Surface Science
Background:
- Electric force microscopy measures electric field fluctuations using a charged probe.
- Noncontact friction measurements probe the dielectric response of materials.
- Previous studies attributed friction over metals to adsorbed molecules.
Purpose of the Study:
- To investigate baseline noncontact friction over bare metal surfaces.
- To calculate noncontact friction for a thin conducting film considering wavevector dependence.
- To complement existing friction calculations for insulators and semiconductors.
Main Methods:
- Theoretical calculation of noncontact friction.
- Utilizing a wavevector-dependent dielectric function for conductors.
- Comparison with dielectric continuum models.
Main Results:
- Wavevector dependence in the dielectric response enhances friction over conductors.
- The dependence of friction on tip-sample separation is altered by wavevector effects.
- The calculation provides a baseline for understanding friction on bare metal surfaces.
Conclusions:
- The wavevector-dependent dielectric function is crucial for accurate friction calculations on conductors.
- This work establishes a theoretical framework for noncontact friction on bare metals.
- Findings contribute to understanding surface interactions and dielectric properties.
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