Resonant polaron coupling of high index electron Landau levels in GaAs heterostructures

The resonant polaron coupling of high index Landau levels was investigated for quasi-two-dimensional electron inversion layers in GaAs. Strong polaron mass enhancements were observed in magnetic field regimes where 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 Fröhlich coupling constant alpha = 0.06 to 0.07 taking into account band coupling phenomena, a finite extent of the inversion layer in growth direction, and coupling of the electrical dipole transitions between the Landau levels due to electron-electron interactions.