Exchange interaction in quantum-wire subbands

The many-electron ground state is studied in a quantum wire with several populated spin and orbital subbands. The many-body effect is treated in the lowest order. The phase diagram of the subband population is obtained as a function of magnetic field and the strength of the confining potential. If the magnetic field is small, there is a phase boundary between spin-polarized states and partially spin-polarized states. Using these results, transport characteristics are calculated using Landauer’s formula and a dip is predicted in the conductance plateau of 2${\mathit{e}}^2$/h.