Zero-Magnetic Field Fractional Quantum States

Abstract

Since the discovery of the Fractional Quantum Hall Effect in 1982 there has been considerable theoretical discussion on the possibility of fractional quantization of conductance in the absence of Landau levels formed by a quantizing magnetic field. Although various situations have been theoretically envisaged, particularly lattice models in which band flattening resembles Landau levels, the predicted fractions have never been observed. In this Letter, we show that odd and even denominator fractions can be observed, and manipulated, in the absence of a quantizing magnetic field, when a low-density electron system in a GaAs based one-dimensional quantum wire is allowed to relax in the second dimension. It is suggested that such a relaxation results in formation of a zig-zag array of electrons with ring paths which establish a cyclic current and a resultant lowering of energy. The behavior has been observed for both symmetric and asymmetric confinement but increasing the asymmetry of the confinement potential, to result in a flattening of confinement, enhances the appearance of new fractional states. We find that an in-plane magnetic field induces new even denominator fractions possibly indicative of electron pairing. The new quantum states described here have implications both for the physics of low dimensional electron systems and also for quantum technologies. This work will enable further development of structures which are designed to electrostatically manipulate the electrons for the formation of particular configurations. In turn, this could result in a designer tailoring of fractional states to amplify particular properties of importance in future quantum computation.

arXiv comment4 figures, 16 pages including supplementary material

References in corpus (16)

• High temperature fractional quantum Hall states
• Fractional quantum Hall states at zero magnetic field
• Fractional quantum Hall effect in the absence of Landau levels
• Fractional Helical Liquids and Non-Abelian Anyons in Quantum Wires
• Wigner crystal physics in quantum wires
• A New Paradigm for Edge Reconstruction in Fractional Quantum Hall States
• Incipient Formation of an Electron Lattice in a Weakly-Confined Quantum Wire
• Pairing in Luttinger Liquids and Quantum Hall States
• Chiral currents in one-dimensional fractional quantum Hall states
• Many-body effects in a quasi-one-dimensional electron gas
• Row coupling in an interacting quasi-one-dimensional quantum wire investigated using transport measurements
• Spin coupling in zigzag Wigner crystals
• All-electrical injection and detection of a spin polarized current using 1D conductors
• Imaging the zigzag Wigner crystal in confinement-tunable quantum wires
• Self-Organised Fractional Quantisation in a Hole Quantum Wire
• Low-temperature illumination and annealing of ultra-high quality quantum wells

Cited by in corpus (9)

• Fractional Conductance in Strongly Interacting 1D Systems
• Engineered spin-orbit interactions in LaAlO${}_3$/SrTiO${}_3$-based 1D serpentine electron waveguides
• Engineering electron wavefunctions in asymmetrically confined quasi one-dimensional structures
• One-dimensional repulsive Hubbard model with mass imbalance: Orders and filling anomaly
• Clock model and parafermions in Rashba nanowires
• One-dimensional Kronig-Penney superlattices at the LaAlO${}_3$/SrTiO${}_3$ interface
• Universal conductance dips and fractional excitations in a two-subband quantum wire
• Modulation induced transport signatures in correlated electron waveguides
• Interacting holes in a gated WSe${}_2$ quantum channel: valley correlations and zigzag Wigner crystal