Adsorption of Na Monolayer on Graphene Covered Pt(111) Substrate

Modification of graphene electronic properties via contact with atoms of different kind allows for designing a number of functional post-silicon electronic devices. Specifically, 2D metallic layer formation over graphene is a promising approach to improving the electronic properties of graphene-based systems. In this work we analyse the electronic and spin structure of graphene synthesized on Pt(111) after sodium monolayer adsorption by means of angle-resolved photoemission spectroscopy and ab initio calculations. Here, we show that sodium layer formation leads to a shift of the graphene pi states towards higher binding energies, but the most intriguing property of the studied system is the appearance of a partially spin-polarized Kanji symbol-like feature resembling the graphene Dirac cone in the electronic structure of adsorbed sodium. Our findings reveal that this structure is caused by a strong interaction between Na orbitals and Pt 5d spin-polarized states, where the graphene monolayer between them serves as a mediator of such interaction.