Phase transitions at filling ν = 5/2 in ZnO heterostructures

ORAL

Abstract

Half-filled Landau levels (LL) elicit competing phases which intimately depend on the nature of inter-particle interaction effects. The competition between emergent Fermi-surfaces, the fractional quantum Hall (FQH) effect and broken symmetry nematic ground states is now well documented. Here we report a complex cascade of phases which exist at filling ν = 5/2 in high mobility ZnO heterostructures and the ability to tune between them by selectively enhancing the Zeeman energy through sample rotation. We are able to induce a series of phase transitions between an incompressible FQH state, a compressible ground state, an anisotropic nematic state and an isotropic insulating state. These occur in the vicinity of the coincidence of the N = 1 and 0 LL as electrons are transferred between opposing spin branches. The even denominator FQH incompressibility only occurs when significant population of N = 1 exists, reinforcing the role of the orbital character of carriers for the development of this ground state. The anisotropic transport shows B-field sweep direction dependent hysteresis, suggesting the underlying nematic texture may be from magnetic domains of electrons of differing spin and orbital character close to the level crossing.

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Presenters

  • Joseph Falson

    • Max Planck Institute for Solid State Research

Authors

  • Joseph Falson

    • Max Planck Institute for Solid State Research

  • Daniela Tabrea

    • Max Planck Institute for Solid State Research

  • ding zhang

    • Department of Physics, Tsinghua University
    • Max Planck Institute for Solid State Research

  • Inti Sodemann

    • Physics, Massachusetts Inst of Tech-MIT
    • Max Planck Insitute for the Physics of Complex Systems

  • Yusuke Kozuka

    • Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo
    • Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), the University of Tokyo
    • Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), Univ. of Tokyo
    • Applied Physics, University of Tokyo

  • Atsushi Tsukazaki

    • Institute for Materials Reaserch, Tohoku University
    • Tohoku Univ
    • Institute for Materials Research, Tohoku University
    • IMR, Tohoku University
    • Institute for Materials Research
    • Tohoku University
    • Tohoku Univ.

  • Masashi Kawasaki

    • Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo
    • Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), the University of Tokyo
    • Univ of Tokyo
    • The University of Tokyo
    • Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo
    • Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), Univ. of Tokyo
    • Applied Physics, University of Tokyo
    • Department of Applied Physics, The University of Tokyo
    • Department of Applied Physics, University of Tokyo

  • Jurgen Smet

    • Max Planck Institute for Solid State Research
    • Max Planck Insitute for Solid State Research