Structural Characterization of 2D Layered Complex Hetero-Ion Systems

Abstract

In this paper, we investigate the coexistence of ferroelectricity (FE) and ferromagnetism (FM) in complex hetero-ion-based lamellar materials at the 2-Dimmensional limit. This combination of properties may provide limitless opportunities for applications in spintronics, ferroelectric photovoltaics, and nonvolatile magnetic memory, all of which offer opportunities to advance computing. By mechanically exfoliating bulk single crystals of metal chalcophosphate sample including, CuInP2S6, CuCrP2Se6, and CuCrP2S6, a top-down approach is used to obtain flakes that are as thin as possible. Atomic Force Microscopy (AFM) was used to measure the thickness of each flake and Raman Spectroscopy to correlate the spectrographic signature to other optical images. Furthermore, studies on heterostructures formed from stacking different monolayers of material in order to study the coupling between different layers are also considered. I have successfully measured a range of flake thickness that correlates to a trend in the intensity of the Raman spectra in three members of the metal chalcophosphate family, CuInP2S6, CuCrP2Se6, and CuCrP2S6. A monolayer of metal chalcophosphate family materials can be further studied to probe for the existence of subnanometer ferroelectric, ferromagnetic, or magnetoelectric multiferroic responses from each respective material systems. This research can be used to formulate a device that can take advantage of its magnetoelectric coupling in terms of reading and writing data.