RESONANT POLARON COUPLING OF HIGH-INDEX ELECTRON LANDAU-LEVELS IN GAAS HETEROSTRUCTURES

The resonant polaron coupling of high index Landau levels was investig ated for quasi-two-dimensional electron inversion layers in GaAs. Stro ng polaron mass enhancements were observed in magnetic field regimes w here the Landau levels N = 2 and 3 cross with the level N = 0 plus one bulk longitudinal optical phonon. The polaron masses were excellently described with a Frohlich coupling constant alpha = 0.06 to 0.07 taki ng into account band coupling phenomena, a finite extent of the invers ion layer in growth direction, and coupling of the electrical dipole t ransitions between the Landau levels due to electron-electron interact ions.