ELECTRON-HOLE PAIR EXCITATION IN A MAGNETO-QUANTUM PLASMA UNDER A ONE-DIMENSIONAL PERIODIC POTENTIAL

We have calculated the frequency dependent dielectric response functio n for a quantum plasma under a constant magnetic field and a one-dimen sional periodic modulation potential. It is found that the original in verse square root divergence in the density of states is removed by th e modulation potential while periodic finite peaks and sudden steps ar e introduced. The electron-hole excitation exhibits two new features d ue to the periodic modulation. (i) the excitation contains double: pea ks at omega around omega(c) and (ii) it also contains a series of kink like structures at the band edges.