Graph Surfaces Invariant by Parabolic screw Motions with Constant Curvature in $ \: \mathbb H^2 \times \mathbb R$

In this work we study vertical graph surfaces invariant by parabolic screw motions with pitch $\ell >0$ and constant Gaussian curvature or constant extrinsic curvature in the product space $\mathbb H^2 \times \mathbb R$. In particular, we determine flat and extrinsically flat graph surfaces in $\mathbb H^2 \times \mathbb R$. We also obtain complete and non-complete vertical graph surfaces in $\mathbb H^2 \times \mathbb R$ with negative constant Gaussian curvature and zero extrinsic curvature.