2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/16814We have performed temperature dependent tunneling experiments through a single impurity in an asymmetric vertical double barrier tunneling structure. In particular in the charging direction we observe at zero magnetic field a clear shift in the onset voltage of the resonant tunneling current through the impurity. With a magnetic field applied the shift starts to disappear. The experimental observations are explained in terms of resonant tunneling through a spin degenerate impurity level.2 pages, 3 figures; 25th International Conference on the Physics of Semiconductors, Osaka, Japan, September 17-22, 2000Mesoscale and Nanoscale Physicstext