Revealing the Secrets of 2D Materials: Nanospectroscopy and Nano-Imaging Illuminate Structure-Property Relationships in Complex Materials

The study of emergent phenomena at room temperature is crucial for the development of new materials and technologies. In van der Waals (vdW) systems, manipulating strain, introducing defects, altering the layer stacking, and functionalizing the surface can potentially be used to control the novel magnetic and electronic properties of these materials. We investigate the origin of novel phenomena using a combination of advanced scanning probe techniques. Synchrotron infrared nanospectroscopy (SINS) combines the broad bandwidth and brightness of synchrotron infrared radiation with scanning near-field optical microscopy (s-SNOM), enabling direct probing of elementary excitations of functional materials spanning the mid- and far-infrared with ~ 20 nm spatial resolution. The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory operates two infrared beamlines (Beamlines 2.4 and 5.4) with SINS instruments.

I will discuss the capabilities of the ALS infrared beamlines by highlighting collaborative research on 2D materials, focusing on lattice strain [2], carrier density [3], and recent technical advances incorporating magnetic force microscopy (MFM), Kelvin probe force microscopy (KPFM), and conductive atomic force microscopy (c-AFM) with SINS to further explore chemical and structural anisotropy in transition metal dichalcogenides (TMDs) [3].



These results are a preview of the advances in understanding of vdW heterostructures to be gained through this multi-probe technique, which is freely available to users with an approved scientific proposal.