APS Logo

A new quantum spin liquid candidate with Co-based triangular lattice

ORAL

Abstract

Currently under active study in condensed matter physics, both theoretically and experimentally, are quantum spin liquid (QSL) states. However, the existing QSL candidates all have their intrinsic disadvantages, and solid evidence for quantum fluctuations is scarce. Here, we report a previously unreported compound, Na2BaCo(PO4)2, a geometrically frustrated system with effective spin-1/2 local moments for Co2+ ions on an isotropic two-dimensional (2D) triangular lattice. Magnetic susceptibility and neutron scattering experiments show no magnetic ordering down to 0.05 K. Thermodynamic measurements show that there is a tremendous amount of magnetic entropy present below 1 K in zero magnetic field. The presence of localized low-energy spin fluctuations is revealed by inelastic neutron measurements. At low applied fields, these spin excitations are confined to low energy and contribute to the anomalously large specific heat. In larger applied fields, the system reverts to normal behavior as evident by both neutron and thermodynamic results. Our experimental characterization thus reveals that this material is an excellent candidate for the experimental realization of a QSL state.

–

Presenters

  • Ruidan Zhong

    Brookhaven National Laboratory, Princeton University

Authors

  • Ruidan Zhong

    Brookhaven National Laboratory, Princeton University

  • Shu Guo

    Princeton University, Chemistry, Princeton University

  • Guangyong Xu

    Center of Neutron Research, National Institute of Standards and Technology, Neutron-Condensed Matter Science Group, National Institute of Standards and Technology, National Institute of Standards and Technology, NIST, Center for Neutron Research, National Institute of Standards and Technology, NIST Center for Neutron Research, Oak Ridge National Laboratory

  • Zhijun Xu

    NIST and University of Maryland, National Institute of Standards and Technology, (NCNR, National Institute of Standards and Technology), NIST Center for Neutron Research

  • Robert J. Cava

    Princeton University, Chemistry, Princeton University, Department of Chemistry, Princeton University, Chemistry, Pinceton University, Princeton Univ