We use magnetotransport measurements to probe quantum Hall ground states in graphene/${\mathrm{WSe}}_2$ heterobilayers. Compared to pristine graphene, inter-Landau level (LL) gaps at half-filled quartets away from filling factor $\nu =0$ show significantly weaker dependence on the magnetic field $B$, while odd $\nu$ fillings show a stronger dependence. We interpret this behavior using a model incorporating Ising and Rashba spin-orbit coupling (SOC) along with Coulomb interactions within the self-consistent Hartree-Fock framework. A model fit yields Ising SOC in range $\sim 1–2 \mathrm{meV}$, Rashba $\sim 10 \mathrm{meV}$, and the in-plane dielectric constant $\sim 12$, in agreement to previously found values. In the zeroth LL quartet, the $\nu =0$ gap as a function of magnetic field exhibits a plateau near 5 T, compared to $\sim 20–25 \mathrm{T}$ for pristine graphene. This behavior is in agreement with a model in which the SOC causes a phase transition from a canted antiferromagnetic state to a ferromagnetic state to occur at a much lower field. Our studies demonstrate how the interplay of SOC and electronic interactions affect graphene's electronic structure.

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• Spin-orbit coupling
• Graphene
• Interfaces
• Transition metal dichalcogenides
• Cryogenics
• Transport techniques