Cosmological evolution of quintessence with a sign-changing interaction in dark sector

Dark energy and dark matter are only indirectly measured though their gravitational effects. It is possibie that there is some direct, non-gravitational interaction between DE and DM, which can be used to solve (or, at least alleviate) several important theoretical problems. In the present work, by analysing the cosmological dynamical system with a dark-sector interaction which changes its sign during the cosmological evolution, we find a scaling attractor to help to alleviate the cosmic-coincidence problem. This result shows that this interaction can bring new features to the cosmology.