  We report new results on the non-conserved dynamics of parallel steps on
vicinal surfaces in the case of sublimation with electromigration and step-step
interactions. The derived equations are valid in the quasistatic approximation
and in the limit $f^{-1}\gg l_D\gg l_{\pm} \gg l_i$, where $f$ is the inverse
electromigration length, $l_D$ the diffusion length, $l_{\pm}$ the kinetic
lengths and $l_i$ the terrace widths. The coupling between crystal sublimation
and step-step interactions induces non-linear, non-conservative terms in the
equations of motion. Depending on the initial conditions, this leads to
interrupted coarsening, anticoarsening of step bunches or periodic switching
between step trains of different numbers of bunches.
