COMPETITION BETWEEN SINGLE-PARTICLE AND MULTIPARTICLE RESONANCES IN TUNNELING

A new mechanism is proposed for the anomalous tunneling transmittance of a double-barrier quantum-well structure doped with a transition-met al impurity and possessing an intrinsic two-dimensional continuum. The new tunneling channels are due to exponentially-narrow single-particl e resonances arising near the edge of a 2D band during tunneling. They are temperature-independent and their contribution to the transmittan ce can exceed the contribution of the Kondo resonance even at temperat ures T<T-K. (C) 1997 American lnstitute of Physics.