MULTIPHOTON-ASSISTED TUNNELING, DYNAMIC LOCALIZATION AND ABSOLUTE NEGATIVE CONDUCTANCE

We report the observation of Absolute Negative Conductance (ANC), mult iphoton stimulated emission and dynamical localization in sequential r esonant tunneling semiconductor superlattices driven by intense terahe rtz electric fields. With increasing terahertz field strength the cond uctance neat zero dc bias decreases towards zero and then becomes nega tive. This is accompanied by new steps and plateaus that are attribute d ia multiphoton-assisted resonant tunneling between ground states of neighboring quantum wells accompanied by the stimulated emission of a photon.