Scanning Tunneling Microscopy Study of Monolayer hBN on α-RuCl₃

At the interface between two non-polar materials, significant charge transfer can occur if there is a work function mismatch. This has recently been exploited to heavily doped graphene by simply placing it in contact with high work function materials such as WO_x and α­-RuCl₃. In this work, we seek to determine whether such charge transfer can occur between two insulating van der Waals materials – namely hexagonal boron nitride (hBN), a wide gap insulator, and α-RuCl₃. It has been predicted that monolayer hBN in contact with α-RuCl₃ leads to significant interlayer charge transfer that induces a massive shift in the component band structures of each material. We will describe experimental investigations of this effect by using optically-enabled scanning tunneling microscopy/spectroscopy (STM/S) and scanning near-field optical microscopy (SNOM).