Tunneling transmission in quantum wires in the presence of magnetic fields

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Abstract
We have investigated the quantum-mechanical transmission of an electron in narrow wires in the presence of perpendicular magnetic fields. When a thin potential barrier is placed across the wire, tunneling transmission through the barrier leads to magnetic-field-induced resonances. The resonances result in quasiregular peaks when the barrier is relatively thick. As the thickness is reduced, mode mixing, which is allowed due to the magnetic field, becomes significant and the transmission turns out to be a mixture of resonant transmisison and reflection. We show that the magnetic field in the barrier is responsible for the enhanced transmission, while the presence of the magnetic field in external leads is crucial for the resonant reflection. We also examine the transmission in a magnetically defined double-barrier structure.