THEORY FOR THE OSCILLATORY CYCLOTRON-RESONANCE EFFECTIVE-MASS IN A HETEROSTRUCTURE

The Hartree-Fock treatment of cyclotron resonance (CR) [see A. H. MacD onald, J. Phys. C 18, 1003 (1985)] is generalized by including the cor relation contribution to the screening by the electrons. It is found t hat the CR effective mass m is an oscillatory function of the magneti c field, which is due to the filling-factor-dependent dynamic screenin g of the electron-impurity scattering. It is demonstrated that as the Landau levels are depleted with increasing magnetic field, m has a ma ximum at half-filling. Similar behavior has also been found in CR abso rption of the two-dimensional electron gas in a high-mobility heterost ructure.