Nature of the spin liquid ground state in a breathing kagome compound studied by NMR and series expansion

Abstract

In the vanadium oxyfluoride compound (NH${}_4$)${}_2$[C${}_7$H${}_{14}$N][V${}_7$O${}_6$F${}_{18}$] (DQVOF), the V${}^{4+}$ (3d${}^1$, $S=1/2$) ions realize a unique, highly frustrated breathing kagome lattice composed of alternately-sized, corner-sharing equilateral triangles. Here we present an ${}^{17}$O NMR study of DQVOF, which isolates the local susceptibility of the breathing kagome network. By a fit to series expansion we extract the ratio of the interactions within the breathing kagome plane, $J_{▽}/J_{△}=0.55(4)$, and the mean antiferromagnetic interaction $\bar{J}=60(7)$~K. Spin lattice, $T_1$, measurements reveal an essentially gapless excitation spectrum with a maximum gap $\Delta /\bar{J}=0.007(7)$. Our study provides new impetus for further theoretical investigations in order to establish whether the gapless spin liquid behavior displayed by DQVOF is intrinsic to its breathing kagome lattice or whether it is due to perturbations to this model, such as a residual coupling of the V${}^{4+}$ ions in the breathing kagome planes to the interlayer V${}^{3+}$ ($S=1$) spins.

5 pages, 4 figures, to appear in Phys. Rev. Lett

References in corpus (6)

• Projected wavefunction study of Spin-1/2 Heisenberg model on the Kagome lattice
• 17O NMR study of the intrinsic magnetic susceptibility and spin dynamics of the quantum kagome antiferromagnet ZnCu3(OH)6Cl2
• Numerical-Diagonalization Study of Spin Gap Issue of the Kagome Lattice Heisenberg Antiferromagnet
• Theory of quantum impurities in spin liquids
• Spin susceptibility of quantum magnets from high to low temperatures
• Effective quantum dimer model for trimerized kagome antiferromagnet

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• Ground-state and thermodynamic properties of the spin-$\frac{1}{2}$ Heisenberg model on the anisotropic triangular lattice
• Emergent skyrmion-based chiral order in zero-field Heisenberg antiferromagnets on the breathing kagome lattice
• Signatures of a magnetic superstructure phase induced by ultrahigh magnetic fields in a breathing pyrochlore antiferromagnet
• High temperature series expansions of S = 1/2 Heisenberg spin models: algorithm to include the magnetic field with optimized complexity
• Logarithmic divergent specific heat from high-temperature series expansions: application to the two-dimensional XXZ Heisenberg model
• Cluster quantum Monte Carlo study of two-dimensional weakly-coupled frustrated trimer antiferromagnets
• Na${}_5$Co${}_{15.5}$Te${}_6$O${}_{36}$: an $S$ = 1/2 stacked Ising kagome antiferromagnet with a partially disordered ground state
• Zero-field miniature skyrmion crystal and chiral domain state in breathing-kagome antiferromagnets
• Nematicity Liquid in a Trimerized-Kagome Antiferromagnet
• Spontaneous chirality selection and nonreciprocal spin wave in breathing-kagome antiferromagnets at zero field
• Nonreciprocal magnon excitations by the Dzyaloshinskii-Moriya interaction on the basis of bond magnetic toroidal multipoles
• Dynamical spin correlations in kagome antiferromagnets: comparison of Abrikosov fermion and Schwinger boson approaches beyond mean field
• Precompression engineering of metal-insulator transition and magnetism in designed breathing kagome systems