CHARACTERISTICS OF THE CONDUCTANCE OF A QUANTUM WAVE-GUIDE CONTAINING AN ARRAY OF STUBS - NUMERICAL-SIMULATION

We present numerical investigations of the conductance of a quantum waveguide containing an array of stubs with disordered stub lengths and ballistic lead connections between the adjacent stubs with the use of the transfer-matrix approach. The profiles of the conductance as a function of the Fermi wave number of the electrons depend on the geometric configuration of the system. The effect on the conductance of geometric scattering and the two different length scales involved in the network, namely, the stub length and the ballistic leads connecting consecutive stubs, is studied. It is found that the conductance decay behavior strongly depends on the type of the geometric parameter fluctuations, the extent of disorder, and the Fermi wave number of the electrons. For the same extent of disorder, the localization length associated with the disordered stub length is shorter than that associated with the disordered ballistic leads connecting consecutive stubs. We also present the statistical distribution of conductance fluctuations in this disordered network system. It can be normal or log-normal, depending on the extent of disorder. Finally, we find that the additivity of the inverse of the localization lengths corresponding to the individual disorders and their combined disorder seems to be valid with good accuracy in the weak disorder regime. © 1995 The American Physical Society.