Novel two-dimensional electronic materials
Dr. Michel P. de Jong, MESA+ Institute for Nanotechnology, University of Twente
Since the discovery of graphene, research on two-dimensional (2D) materials with exceptional electronic properties has been booming. Some of these materials not only exhibit Dirac fermions like graphene, but also offer other favorable properties such as a sizeable and/or tunable band gap, 2D topological insulator behavior, superconductivity, magnetism, etc.
In this talk I will highlight two novel 2D electronic materials, silicene and VSe2. Silicene, the silicon analogue of graphene, consists of an atomically buckled honeycomb lattice of silicon atoms. Theory predicts a topological spin Hall insulator phase for this Dirac material. Epitaxial silicene has been synthesized on various substrates, however its chemical sensitivity hampers incorporation in layer stacks. We demonstrate experimentally that epitaxial silicene and hexagonal boron nitride (h-BN) can be stacked, without perturbing the electronic properties of silicene. The h-BN protects the silicene from oxidation in air up to several hours, which is an essential step towards the development of layer stacks that allow for fabrication of devices.
VSe2 is a layered transition-metal dichalcogenide that has received attention due to its magnetic properties and charge density wave behavior. We show that single-layer VSe2 grown on graphite by molecular beam epitaxy exists in the metallic 1T-phase, and does not exhibit ferromagnetism down to 16 K.