Interplay of instabilities in mounded surface growth

We numerically study a one-dimensional conserved growth equation with competing linear (Ehrlich-Schwoebel) and nonlinear instabilities. As a control parameter is varied, this model exhibits a non-equilibrium phase transition between two mounded states, one of which exhibits slope selection and the other does not. The coarsening behavior of mounds in these two phases is studied in detail. In the absence of noise the steady-state configuration depends crucially on which of the two instabilities dominates the early time behavior.