Bound states and transmission antiresonances in parabolically confined cross structures: influence of weak magnetic fields

TL;DR

This study investigates how weak magnetic fields influence bound states and conductance antiresonances in parabolically confined quantum wire cross structures, revealing new quasibound states and experimental evidence of their existence.

Contribution

It introduces the effect of weak magnetic fields on quasibound states in parabolically confined quantum wire structures, highlighting the formation of new states and conductance minima not previously characterized.

Findings

Magnetic fields induce new quasibound states in stubbed quantum wires.

Conductance minima correlate with quasibound states formed by magnetic effects.

Experimental evidence supports the theoretical predictions of these states.

Abstract

The ballistic conductance through a device consisting of quantum wires, to which two stubs are attached laterally, is calculated assuming parabolic confining potentials of frequencies $\omega_w$ for the wires and $\omega_s$ for the stubs. As a function of the ratio $\omega_w/\omega_s$ the conductance shows nearly periodic minima associated with quasibound states forming in the stubbed region. Applying a magnetic field B normal to the plane of the device changes the symmetry of the wavefunctions with respect to the center of the wires and leads to new quasibound states in the stubs. The presence of the magnetic field can also lead to a second kind of state, trapped mainly in the wires by the corners of the confining potentials, that yields conductance minima as well. In either case, these bound states form for weak B and strong confining frequencies and thus are not edge states. Finally, we show experimental evidence for the presence of these quasi-bound states.