Edge-channel transport through quantum wires with a magnetic quantum dot

We investigate the scattering of edge channels by a magnetic quantum dot, which is formed by two di/erent magnetic 0elds B∗ and B0 inside and outside the dot, respectively, in a quantum wire. We calculate the two-terminal conductance (G) of the wire and 0nd that for (=B∗=B0)? 0, G is quantized, while for i 0 it is not quantized. This feature results from the di/erent magnetic con0nements, caused by nonuniform magnetic 0elds, between the two cases. ? 2002 Elsevier Science B.V. All rights reserved. PACS: 72.15.Gd; 73.23.Ad