Enhancement of tunneling from a correlated 2D electron system by a many-electron Mossbauer-type recoil in a magnetic field

We consider the effect of electron correlations on tunneling from a 2D elec tron layer in a magnetic field parellel to the layer. A tunneling electron can exchange its momentum with other electrons, which leads to an exponenti al increase of the tunneling rate compared to the single-electron approxima tion. The effect depends on the interrelation between the dynamics of tunne ling and momentum exchange. The results explain and provide a no-parameter fit to the data on electrons on helium. We also discuss tunneling in semico nductor heterostructures.