Searching for Multiferroic Coupling in Stacked Chalcophosphate Heterostructures

We report on our progress in the device design and fabrication of van der Waals heterostructures that exhibit magnetoelectric coupling detectable in transport measurements. To find suitable materials with magnetic or ferroelectric ordering, we draw from the chalcophosphate chemical family grown via reactive flux methods. These materials are desirable because of their wealth of material properties¹ and ease of mechanical exfoliation². However, direct transport measurements on thin films of these materials can be challenging because they are often Mott or charge-transfer insulators³. To overcome this hurdle, we focus on a three layer geometry comprised of an ferroelectrically ordered material, a spin-orbit coupled conductor, and a magnetically ordered material, with the goal of coupling the ferroelectric and magnetic orders in the conducting behavior of the full stack. Construction of the stack on our home-built stacking stage, material characterization, and  the quality of the intefaces in the devices are discussed, as are transport measurements looking for signatures of the aforementioned magnetoelectric coupling.

[1] M Zhou. Mat. Horiz. 7, 2020

[2] S. Son, 2D Mat., 7, 2020

[3] M. A. Susner, Adv. Mater., 29, 2017