Multichannel ballistic magnetotransport through quantum wires with double circular bends

Abstract

A theoretical study of magnetotransport through two-dimensional quantum wires with double circular bends is made within the ballistic approximation. By means of the mode-matching method, the S matrix of the single bend with a hard-wall confining potential is calculated as a function of the magnetic field or the Fermi energy for the bending radius and the bending angle as parameters. The combination of S matrices is performed for bends in series. The technique is applied to systems consisting of double bends. The symmetry properties of the S matrix are clarified for the two-terminal systems with rotational symmetry or mirror-plane symmetry. The transmission matrix is evaluated in detail for the case of three propagating channels. The strong dependence of the interchannel scattering on the magnetic field is found. The structure of dips (antiresonances) appearing in the conductance is studied as a function of the distance between bends.