Giant magnetic suppression of tunneling out of a 2D electron system

L. Menna, S. Yücel, and E. Y. Andrei
Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08855

We have measured tunneling rates out of an electron layer trapped at a liquid-helium—vacuum interface in the presence of a magnetic field. When the field is transverse to the escape direction we find a striking suppression of the tunneling rates: a field of 3000 G at 40 mK reduces the tunneling current by four orders of magnitude. As the temperature increases the magnetic suppression of tunneling diminishes until it disappears completely above 250 mK. By contrast parallel fields have no effect on the tunneling rates.