2018/10/23 by Sanjeev Kumar, S. Kumar, M. Pepper +6 · 1 citation
Physics and Astronomy · #Asymmetry #Condensed matter physics #Electron #Flattening #Fractional quantum Hall effect #Landau quantization #Magnetic field #Physics #Quantization (signal processing) #Quantum #Quantum Hall effect #Quantum and electron transport phenomena #Quantum dot #Quantum mechanics #Quantum spin Hall effect #Surface and Thin Film Phenomena #Topological Materials and Phenomena #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/physrevlett.122.086803
published as Phys. Rev. Lett. 122, 086803 (2019) · 4 figures, 16 pages including supplementary material
arxiv created 2018/10/23 · openalex publication_date 2019/02/28 · arxiv updated 2019/03/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 zigzag 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.