Far-infrared-active collective modes of short-period arrays of quantum dots and antidots

In this paper we investigate the far-infrared absorption of short period arrays of quantum dots and antidots and its underlying collective modes. For weak perpendicular magnetic fields when the magnetic length approaches the periodic length of the lattice the band structure manifests itself in the absorption. In high magnetic fields both systems show the characteristic two-peak structure, connected to the center-of-mass motion of quantum dots, and the edge and bulk modes of antidots. In the intermediate region the magnetoplasmon splits into Bernstein modes. The interaction between the electrons is treated in the Hartree approximation on equal footing in the ground state and the absorption calculation, both for the intradot and interdot case. [S0163-1829(98)06607-7].