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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).

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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