Rapid infrared imaging for rhombohedral graphene

TL;DR

This paper introduces a rapid infrared imaging method to distinguish ABC-stacked multilayer graphene from ABA stacking with high accuracy, enhancing efficiency in studying strongly correlated electronic phenomena.

Contribution

The study presents a new infrared imaging technique for quick, accurate identification of stacking sequences in multilayer graphene, surpassing traditional methods in speed and consistency.

Findings

Infrared imaging clearly differentiates ABC and ABA stacking.

The method offers higher throughput than Raman microscopy.

Integration with dry transfer techniques is demonstrated.

Abstract

The extrinsic stacking sequence based on intrinsic crystal symmetry in multilayer two-dimensional materials plays a significant role in determining their electronic and optical properties. Compared with Bernal-stacked (ABA) multilayer graphene, rhombohedral (ABC) multilayer graphene hosts stronger electron-electron interaction due to its unique dispersion at low-energy excitations and has been utiliazed as a unique platform to explore strongly correlated physics. However, discerning the stacking sequence has always been a quite time-consuming process by scanning mapping methods. Here, we report a rapid recognition method for ABC- stacked graphene with high accuracy by infrared imaging based on the distinct optical responses at infrared range. The optical contrast of the image between ABC and ABA stacked graphene is strikingly clear, and the discernibility is comparable to traditional optical Raman microscopy but with higher consistency and throughput. We further demonstrate that the infrared imaging technique can be integrated with dry transfer techniques commonly used in the community. This rapid and convenient infrared imaging technique will significantly improve the sorting efficiency for differently stacked multilayer graphene, thereby accelerating the exploration of the novel emergent correlated phenomena in ABC stacked graphene.