  Dual-unitary quantum circuits can be used to construct 1+1 dimensional
lattice models for which dynamical correlations of local observables can be
explicitly calculated. We show how to analytically construct classes of
dual-unitary circuits with any desired level of (non-)ergodicity for any
dimension of the local Hilbert space, and present analytical results for
thermalization to an infinite-temperature Gibbs state (ergodic) and a
generalized Gibbs ensemble (non-ergodic). It is shown how a tunable
ergodicity-inducing perturbation can be added to a non-ergodic circuit without
breaking dual-unitarity, leading to the appearance of prethermalization
plateaux for local observables.
