EFFECT OF VARIOUS OBSTACLES ON OSCILLATORY MAGNETOCONDUCTANCE OF QUANTUM DOUBLE-COUPLED CHANNELS

The characteristics of the magnetoconductance of a nonuniform electron waveguide containing various shaped obstacles are investigated by usi ng a model of two-coupled tight-binding chains and the transfer-matrix approach. The variation of the magnetoconductance as a function of to tal magnetic flux PHI threading the obstacle region is presented. The effect of the interchain tunneling modulation on the magnetoconductanc e for double-mode and single-mode transport processes is different. Wh en the energy of the incident electrons is just above the threshold en ergy for the opening of the second propagating mode at zero magnetic f ield, at some magnetic flux, the conductance abruptly decreases owing to the presence of mode quenching. The magnetoconductance for various multiply connected structures and one-dimensional superlattice (1DSL) type tunneling modulation structures is also evaluated. Owing to the p resence of the miniband gaps to be formed by IDSL structures, differen t patterns in the magnetoconductance are found.