We have derived an exact Breit-Wigner formula for the conductivity of a strongly disordered system using the Schwinger-Keldysh Green’s-function method. Using this theory we study a generalized one-dimensional Anderson model (with random site energies and random hopping matrix elements) in the present paper. Numerical calculations show that our model describes the coherent feature of resonant tunneling in strongly disordered mesoscopic systems. If one single-site energy is changed, the magnitude of steady current changes drastically; in fact, resonant tunneling can be destroyed.

• Received 15 September 1992

DOI:https://doi.org/10.1103/PhysRevB.47.10654