Quantum Matter Seminar

Van der Waals (vdW) interfaces are emerging as a versatile platform to control and investigate electronic, magnetic and optical properties of quantum materials. I will discuss nano-optical studies of charge transfer across an interface of vdW materials with different work functions. Charge transfer between graphene and a-RuCl3 (a candidate Kitaev spin liquid material) prompts metallicity in the graphene layer. We also observed indications for the electronic response in a-RuCl3 initiated by charge transfer with graphene. We implemented a complementary class of charge-transfer structure produced oxidation of vdW monolayers of WSe2 and ZrSe2. These latter structures reveal ambipolar charge transfer along with prominent plasmonic effects in graphene. If time permits, I will also discuss negative refraction of polaritonic waves at the interface of two vdW materials hBN and MoO3. All these experiments were enabled by nano-optical instrumentation developed in our group at Columbia.