Incipient Formation of an Electron Lattice in a Weakly-Confined Quantum Wire

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.