Acoustic surface plasmons in type-II semiconducting superlattices

The spectrum of electronic collective excitations of a semi-infinite type-II semiconducting superlattice contains two novel surface polariton branches, one of which is an acoustic surface plasmon. As a result of the quantized nature of the electronic motion within the layers, this new type of surface polariton does not suffer Landau damping. The acoustic branch is of particular interest because the group velocity of this mode can be controlled by sample preparation, making these systems potentially useful for surface-wave devices.