Momentum resolved tunneling study of interaction effects in 1D electron systems

The physics of electrons confined to one dimension (1D) is qualitatively different from higher dimensional cases. Electron-electron interactions in 1D have a unique influence on the system properties; leading to a collective behavior and rendering the Fermi liquid theory inapplicable. In this work we study several manifestations of the exceptional properties of 1D electron systems.;Studying low energy excitations, we confirm the existence of fractionally-charged modes in the wires, as predicted by Luttinger liquid theory. Furthermore, when energetic particles are injected into the wire we find strong disparity between relaxation properties of electrons and holes. This result is explained through energy and momentum conservation considerations, but requires accounting for dispersion nonlinearity, and provides a unique experimental manifestation of interacting electrons beyond the Luttinger liquid limit.;Quantum Hall effect edge states provide another manifestation of quasi-1D current carrying states. The spatial charge and spin structure of these edge states is determined by a competition between the confinement potential and the e-e interaction, which leads to nontrivial 'edge reconstruction' arrangements. Qualitatively similar effects are expected for non-chiral 1D conductors under perpendicular magnetic fields. We find that under strong perpendicular magnetic fields a spin polarized strip is created in the cross section of the wire, demonstrating a theoretically predicted but so far unobserved form of charge reconstruction. Furthermore, we find a new form of charge reconstruction, in which Coulomb interactions lead to a close alignment of Fermi points of different 1D modes. A Hartree-Fock calculation is used to explain these measurements.;Our experimental approach is based on momentum-resolved tunneling between two parallel quantum wires, one of which is situated at the edge of a populated two dimensional electron gas. The system is fabricated using cleaved-edge overgrowth in a GaAs/AlGaAs heterostructure. We measure the tunneling conductance between the two wires, while selectively allowing electrons with a specific momentum and energy from one wire to tunnel into a specific energy and momentum state in the other.