heterostructures*

Twisted layers of van der Waals materials have been studied intensely in recent years. These materials can be thinned down to one layer and vertically stacked on top of each other to realize heterostructures. By changing parameters such as strain, stacking, external fields, doping, and twist angle, the physical properties of these structures can be manipulated. In this work, we fabricated a device consisting of two transition metal dichalcogenide (TMD) semiconductors, MoSe₂ and WSe₂. By stacking these layers on top of one another, the interaction between layers can form a periodic superlattice potential, known as a moiré potential. Upon optical excitation of MoSe₂/WSe₂ heterostructure, indirect interlayer excitons (IXs) form, which comprise an electron in the MoSe₂ layer bound to a hole in WSe₂ layer. The IX in this structure has several astonishing properties, including long lifetime and the permanent dipole moment. I will discuss our recent advances, separating the TMD layers using a bilayer hBN spacer layer which suppresses the moiré potential. I will discuss our recent measurements quantifying the flow of IXs in hBN separated heterostructures, which has been proposed as a promising platform for realizing high temperature superfluidity. Specifically, I will discuss the effects of temperature, doping, magnetic field and IX density on IX diffusion.