Volcanism and plate tectonics on super-Earths

Geodynamics and Rate of Volcanism on Massive Earth-like Planets

Lots of stuff in there: firstly it may not be necessary to have plate tectonics to maintain a habitable climate, but planets with plate tectonics stay active (and thus habitable - if habitability depends on recycling CO₂ into the atmosphere) for longer. It might be harder for plate tectonics to operate on massive planets because the crust would be more buoyant and hence more difficult to subduct.