Effect of temperature and magnetic field on the 0.7 structure in a ballistic one-dimensional wire

Low temperature measurements of ballistic one-dimensional (1D) wires show an additional structure at 0.7(2e2/h) in the conductance characteristics (Phys. Rev. Lett. 77 (1996) 135; Phys. Rev. B 62 (2000) 10 950). This 0.7 structure develops into a plateau at e2/h, if, either the in-plane magnetic field is increased (Phys. Rev. Lett. 77 (1996) 135) or the carrier density is decreased (Phys. Rev. B 61 (2000) 13 365). A suggested explanation for this effect is based on spin polarisation induced by many-body interactions. As temperature increases, the e2/h plateau in a magnetic field shifts to 0.6(2e2/h), whereas other plateaus remain unchanged. We study the effect of temperature on the evolution of the 0.7 structure with increasing in-plane magnetic field.