MAGNETOCONDUCTANCE OSCILLATIONS OF 2 PARALLEL QUANTUM WIRES COUPLED THROUGH A POTENTIAL BARRIER

The magnetotransport properties of dual quantum wires, in which two pa rallel quasi-one-dimensional quantum wires are coupled through a thin isolating potential barrier, are studied theoretically. It is found th at the quantized conductance of such a structure as a function of Ferm i energy or magnetic field exhibits square-wave-like oscillations. Thi s character of the conductance is closely related to the energy-disper sion spectrum of electron in the device. Energy-dispersion relations o f the structure with various coupling strengths and magnetic-field str engths are calculated and analyzed in detail. It is found that the mag netic field separates the two sets of dispersion curves that belong to different quantum wires in the wave-number space and that the couplin g effect between quantum wires introduces energy splits at the cross p oints of dispersion curves. In the resonant-tunneling regions a pair o f edge states around the barrier region with oppositely moving directi ons are coupled and form a circulating localized state, leading to the quenching of the related propagation modes. The resulting dispersion relations exhibit an oscillation structure superimposed on the bulk La ndau levels. It is the oscillatory behavior of the dispersions that le ads to the appearance of square-wave modulations in the conductance. T he depth and width of the square wave in conductance depend on the str ength of the magnetic field applied, the Fermi energy of the electron, and the thickness and height of the isolating potential barrier and w idths of the quantum wires. These conductance characteristics may prov ide potential applications to the fabrication of quantum devices.