Spin-Incoherent Transport in Quantum Wires
  When a quantum wire is weakly confined, a conductance plateau appears at e^2/h with decreasing carrier density in zero magnetic field accompanied by a gradual suppression of the 2e^2/h plateau. Applying an in-plane magnetic field B|| does not alter the value of this quantization; however, the e^2/h plateau weakens with increasing B|| up to 9 T, and then strengthens on further increasing B||, which also restores the 2e^2/h plateau. Our results are consistent with spin-incoherent transport in a one-dimensional wire. 
W. K. Hew, K. J. Thomas, M. Pepper, I. Farrer, D. Anderson, G. A. C.   Jones and D. A. Ritchie