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Updated: Jun 3, 2026
08:23
Finite Element Modelling of a Cellular Electric Microenvironment
Published on: May 18, 2021
Sample-to-sample fluctuations of electrostatic forces generated by quenched charge disorder
David S Dean1, Ali Naji, Rudolf Podgornik
1Laboratoire de Physique Théorique (IRSAMC), Université de Toulouse, UPS and CNRS, Toulouse, France.
Summary
Randomly charged surfaces exhibit long-range electrostatic interactions. Fluctuations in both normal and lateral forces reveal insights into charge disorder, aiding experimental characterization.
Area of Science:
- Physics
- Surface Science
- Electrostatics
Background:
- Net neutral surfaces with random charge distributions can generate long-range electrostatic interactions.
- These interactions exhibit sample-to-sample fluctuations due to the specific charge disorder realization.
- Understanding these fluctuations is crucial for characterizing disordered systems.
Purpose of the Study:
- To analyze fluctuations of electrostatic forces in parallel slab and sphere-plane geometries.
- To investigate both normal and lateral force fluctuations, including those with zero mean.
- To explore the potential of measuring lateral force fluctuations for characterizing charge disorder.
Main Methods:
- Utilized the proximity force approximation to analyze force fluctuations.
- Computed exact fluctuations for normal forces with finite mean values.
- Investigated the presence and scaling behavior of lateral force fluctuations.
Main Results:
- Confirmed finite mean values and computed exact fluctuations for normal forces.
- Demonstrated the surprising presence of fluctuations in lateral forces, despite a zero mean.
- Showed that lateral force fluctuations exhibit the same scaling behavior as normal force fluctuations.
Conclusions:
- Lateral force fluctuations provide a novel, complementary method for estimating charge disorder magnitudes.
- Measuring lateral force fluctuations can enhance the characterization of experimental systems with charge disorder.
- The findings offer new avenues for understanding electrostatic interactions in disordered surfaces.
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