Effects of Confining Geometry on Ballistic Transport in Quantum Wires

The effects of confining geometry are investigated on ballistic transport in quasi-one-dimensional quantum wires. The coupled channel type method is used in order to calculate the conductance of the quantum wires as a function of the Fermi energy. It is shown that oscillations existing in the conductance of the wire with a confining potential of `step wise' type geometry disappear as the variation of the confining geometry becomes smooth. In the wire with an extended part irrespective of its geometry, step wise or smooth, the conductance shows dip structures. In the wire with double constrictions, there appear oscillations in the conductance, which can be considered to reflect the existence of resonance and bound states between these two constrictions. The effects of the external magnetic field on ballistic transport are studied in the above-mentioned wires as well.