# Machine Learning Microscopic Form of Nematic Order in twisted double-bilayer graphene

## TL;DR

This paper demonstrates how convolutional neural networks can analyze STM data to learn microscopic nematic order parameters in twisted double-bilayer graphene, distinguishing them from heterostrain effects.

## Contribution

It introduces a CNN-based approach to extract microscopic nematic order from STM data in moiré superlattices, accounting for correlations and heterostrain.

## Key findings

- CNN can learn microscopic nematic order parameters.
- Including energy correlations improves model accuracy.
- Neural networks distinguish nematic order from heterostrain.

## Abstract

Modern scanning probe techniques, like scanning tunneling microscopy (STM), provide access to a large amount of data encoding the underlying physics of quantum matter. In this work, we analyze how convolutional neural networks (CNN) can be employed to learn effective theoretical models from STM data on correlated moir\'e superlattices. These engineered systems are particularly well suited for this task as their enhanced lattice constant provides unprecedented access to intra-unit-cell physics and their tunability allows for high-dimensional data sets within a single sample. Using electronic nematic order in twisted double-bilayer graphene (TDBG) as an example, we show that including correlations between the local density of states (LDOS) at different energies allows CNNs not only to learn the microscopic nematic order parameter, but also to distinguish it from heterostrain. These results demonstrate that neural networks constitute a powerful methodology for investigating the microscopic details of correlated phenomena in moir\'e systems and beyond.