Evidence for a pressure-induced gapped spin-liquid ground state in a coupled ladder antiferromagnet C<sub>9</sub>H<sub>18</sub>N<sub>2</sub>CuBr<sub>4</sub>

ORAL

Abstract

Here we present a comprehensive neutron scattering study on a spin-1/2 coupled ladder antiferromagnet C9H18N2CuBr4 (DLCB for short) under applied hydrostatic pressure. In DLCB, the inter-ladder coupling is sufficiently strong to drive the system to the long-range antiferromagnetic ordering phase below TN=2 K [1]. Analysis of the spin Hamiltonian suggests that DLCB is close to the quantum critical point in two dimensions at ambient pressure and zero field [2]. Single-crystal neutron diffraction measurements under pressure suggest that the magnetic order breaks down above a ciritical pressure Pc~1.0 GPa. By contrasting with quantum Monte Carlo calculations of the dynamic structure factor, the follow-up inelastic neutron scattering study above Pc reveals evidence of a gapped spin-liquid phase with the Z2 topological order, characterized by excitation spectra of fully gapped visons and deconfined spinons.

References:
[1] T. Hong et al., Phys. Rev. B 89, 174432 (2014).
[2] T. Hong et al., Nat. Phys. 13, 638 (2017).

*This research used resources at the High Flux Isotope Reactor and Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory (ORNL).

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Presenters

  • Tao Hong

    • Oak Ridge National Lab
    • Neutron Scattering Division, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory
    • Oak Ridge National Lab, Neutron Scattering Division

Authors

  • Tao Hong

    • Oak Ridge National Lab
    • Neutron Scattering Division, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory
    • Oak Ridge National Lab, Neutron Scattering Division

  • Tao Ying

    • Harbin Institute of Technology

  • Qing Huang

    • University of Tennessee
    • Department of Physics & Astronomy, University of Tennessee
    • University of Tennessee, Knoxville
    • Department of Physics, University of Tennessee
    • Physics, University of Tennessee, Knoxville
    • Department of Physics and Astronomy, University of Tennessee, Knoxville

  • Sachith Dissanayake

    • Department of Physics, Duke University
    • Department of Physics, Duke University, Durham, North Carolina, USA
    • Physics, Duke University
    • Oak Ridge National Lab
    • Duke University
    • Oak Ridge National Laboratory

  • Yiming Qiu

    • Center for Neutron Research, National Institute of Standards and Technology
    • National Institute of Standards and Technology
    • NIST
    • NIST Center for Neutron Research, National Institute of Standards and Technology

  • Mark M Turnbull

    • Clark University

  • Andrey Podlesnyak

    • Neutron Scattering Division, Oak Ridge National Laboratory
    • Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennesse
    • Oak Ridge National Lab

  • Yan Wu

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Huibo Cao

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
    • Neutron Scattering Division, Oak Ridge National Laboratory
    • Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
    • Oak Ridge Natl Lab

  • David Tennant

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Kai Schmidt

    • Universität Erlangen-Nürnberg

  • Stefan Wessel

    • RWTH Aachen University
    • RWTH - Aachen