Spin-valley Silin modes in graphene with substrate-induced spin-orbit coupling

In the presence of external magnetic field Fermi-liquid state supports oscillatory spin modes known as Silin modes. We predict existence generalized in a multivalley system, monolayer graphene. A gauge- and Berry-gauge- invariant kinetic equation for Fermi liquid is developed applied to case graphene with extrinsic spin-orbit coupling (SOC). The interplay SOC Berry curvature allows excitation valley-staggered-spin channels via an AC electric field. resonant contributions from these optical conductivity are calculated.