Moir\'e Fringes in Conductive Atomic Force Microscopy

TL;DR

This paper reports the observation of moiré fringes in conductive atomic force microscopy scans on a ferroelectric material, revealing how experimental parameters influence these patterns and their implications for local transport measurements.

Contribution

It demonstrates that moiré fringes in cAFM are caused by a superposition of scan parameters and sample properties, providing guidelines to distinguish intrinsic from extrinsic effects.

Findings

Moiré fringes arise from scan and sample superposition.

Experimental parameters significantly affect moiré pattern formation.

Potential to enhance measurement resolution using moiré effects.

Abstract

Moir\'e physics plays an important role for the characterization of functional materials and the engineering of physical properties in general, ranging from strain-driven transport phenomena to superconductivity. Here, we report the observation of moir\'e fringes in conductive atomic force microscopy (cAFM) scans gained on the model ferroelectric Er(Mn,Ti)O$_3$. By performing a systematic study of the impact of key experimental parameters on the emergent moir\'e fringes, such as scan angle and pixel density, we demonstrate that the observed fringes arise due to a superposition of the applied raster scanning and sample-intrinsic properties, classifying the measured modulation in conductance as a scanning moir\'e effect. Our findings are important for the investigation of local transport phenomena in moir\'e engineered materials by cAFM, providing a general guideline for distinguishing extrinsic from intrinsic moir\'e effects. Furthermore, the experiments provide a possible pathway for enhancing the sensitivity, pushing the resolution limit of local transport measurements by probing conductance variations at the spatial resolution limit via more long-ranged moir\'e patterns.