  We study the low-temperature transport properties of 1D quantum wires as the
confinement strength V_conf and the carrier density n_1D are varied using a
combination of split gates and a top gate in GaAs/AlGaAs heterostructures. At
intermediate V_conf and n_1D, we observe a jump in conductance to 4e^2/h,
suggesting a double wire. On further reducing n_1D, plateau at 2e^2/h returns.
Our results show beginnings of the formation of an electron lattice in an
interacting quasi-1D quantum wire. In the presence of an in-plane magnetic
field, mixing of spin-aligned levels of the two wires gives rise to more
complex states.
