Proximity-induced Ising spin orbit coupling in bilayer graphene/WSe2 van der Waals heterostructures

Interlayer proximity effects at van der Waals interfaces provide a tool for engineering electronic phases that do not occur in isolated two-dimensional materials. A longstanding goal is proximity induced spin orbit coupling (SOC) in graphene. While previous experimental efforts have reported signatures of SOC in graphene-transition metal dichalcogenide (TMD) heterostructures, these studies have primarily relied on indirect charge and spin transport measurements preventing definitive resolution of the strength, nature, or origin of the induced SOC. Here we report on the direct observation of proximity induced SOC in bilayer graphene in contact with tungsten selenide (WSe2). Using spin- and layer-resolved broken symmetry Landau levels as a probe of layer specific proximity-induced SOC, we observe rearrangement of these levels consistent with an Ising (valley-Zeeman) type SOC with a strength of ≈2 meV. Our observations pave the way toward new engineered topological phases in van der Waals heterostructures.