The intense research in layered materials, like graphite, showed the rich physics and promising prospective of 2D materials and monolayer, as graphene. Still one question remains open: what is the nature of the electrons dynamic between the layers of 2D materials? This is relevant not only for basic science, but also an important issue for application of artificial van der Waals heterostructures, where the conduction path is perpendicular to the layers. The reason for the limited number of investigations comes from an evident practical limit. High quality single crystals, necessary to study the electronic properties, have naturally a reduced thickness in the out-of-plane direction, making the measurement of transport properties along c-axis unpractical.
We overcome this limit using the focused ion beam to microstructure and electrically contact crystals of few µm size. First results were collected on transition metal dichalcogenides, studying the effect of different crystallographic phases, long range order and intercalation. The investigation is completed by measurement under external parameters as high pressure and magneto transport measurements.
Our results call for a new point of view on 2D electronic materials. Experimental evidence shows that out-of-plane transport provides new insight into electronic properties of layered materials.