title: Interaction effects at crossings of spin-polarized one-dimensional subbands.
abstract: We report conductance measurements of ballistic one-dimensional (1D) wires defined in GaAs/AlGaAs heterostructures in an in-plane magnetic field, B. When the Zeeman energy is equal to the 1D subband energy spacing, the spin-split subband N upward arrow intersects (N+1) downward arrow, where N is the index of the spin-degenerate 1D subband. At the crossing of N=1 upward arrow and N=2 downward arrow subbands, there is a spontaneous splitting giving rise to an additional conductance structure evolving from the 1.5(2e(2)/h) plateau. With further increase in B, the structure develops into a plateau and lowers to 2e(2)/h. With increasing temperature and magnetic field the structure shows characteristics of the 0.7 structure. Our results suggest that at low densities a spontaneous spin splitting occurs whenever two 1D subbands of opposite spins cross.
authors.affiliation: Cavendish Laboratory, Madingley Road, Cambridge, CB3 OHE, United Kingdom.
authors.forename: A C
authors.initials: AC
authors.lastname: Graham
authors.forename: K J
authors.initials: KJ
authors.lastname: Thomas
authors.forename: M
authors.initials: M
authors.lastname: Pepper
authors.forename: N R
authors.initials: NR
authors.lastname: Cooper
authors.forename: M Y
authors.initials: MY
authors.lastname: Simmons
authors.forename: D A
authors.initials: DA
authors.lastname: Ritchie