Moiré fringes in conductive atomic force microscopy

Abstract

Moiré physics plays an important role in characterization of functional materials and engineering of physical properties in general, ranging from strain-driven transport phenomena to superconductivity. Here, we report on the observation of moiré fringes in conductive atomic force microscopy (cAFM) scans gained on the model ferroelectric Er(Mn,Ti)O3. By performing a systematic study of the impact of key experimental parameters on the emergent moiré 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 moiré effect. Our findings are important for the investigation of local transport phenomena in moiré engineered materials by cAFM, providing a general guideline for distinguishing extrinsic from intrinsic moiré 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 moiré patterns.