ImpurityAssisted Inelastic Tunneling: ManyElectron Theory
Abstract
The oneelectron theory of impurityassisted tunneling is extended to a manyelectron system. A formal derivation of the wave function through second order in the interaction potential is given for an arbitrary barrier potential and an arbitrary interaction potential. Application to a onedimensional squarebarrier model with energyloss mechanisms confined to the barrier region is made. The magnitude of the inelastic current resulting from the excitation of a molecular impurity is in agreement with the results of the transferHamiltonian model if the appropriate currentcarrying wave functions are used to calculate the transfer matrix elements. Additional secondorder terms which give rise to logarithmic singularities and stepfunction decreases in the barrierpenetration factor are found for interaction potentials which are large near the boundaries of the tunnel barrier. Numerical calculations show that, for a molecular impurity at the boundary, the line shapes in d^{2}IdV^{2} versus V are fundamentally different from those for an impurity inside the barrier by more than ~ 1/2 K.
 Publication:

Physical Review B
 Pub Date:
 September 1970
 DOI:
 10.1103/PhysRevB.2.1714
 Bibcode:
 1970PhRvB...2.1714D