# Force-gradient sensitive Kelvin probe force microscopy by dissipative electrostatic force modulation

## TL;DR

This paper introduces a simplified and faster Kelvin probe force microscopy method that detects electrostatic force gradients via dissipation signals, enabling high-resolution surface potential imaging.

## Contribution

The paper presents a novel KPFM technique using dissipation signals to measure electrostatic force gradients, eliminating the need for low frequency modulation and improving scanning speed.

## Key findings

- Quantitative agreement with traditional KPFM methods.
- Faster scanning without low frequency modulation.
- Effective detection of electrostatic force gradients.

## Abstract

We report a Kelvin probe force microscopy (KPFM) implementation using the dissipation signal of a frequency modulation atomic force microscopy that is capable of detecting the gradient of electrostatic force rather than electrostatic force. It features a simple implementation and faster scanning as it requires no low frequency modulation. We show that applying a coherent ac voltage with two times the cantilever oscillation frequency induces the dissipation signal proportional to the electrostatic force gradient which depends on the effective dc bias voltage including the contact potential difference. We demonstrate the KPFM images of a MoS$_2$ flake taken with the present method is in quantitative agreement with that taken with the frequency modulated Kelvin probe force microscopy technique.