Nature of the spin liquid ground state in a breathing kagome compound studied by NMR and series expansion
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In the vanadium oxyfluoride compound (NH4)2[C7H14N][V7O6F18] (DQVOF), the V4+ (3d1, S=1/2) ions realize a unique, highly frustrated breathing kagome lattice composed of alternately sized, corner-sharing equilateral triangles. Here we present an 17O 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∇/JΔ = 0.55(4), and the mean antiferromagnetic interaction J = 60(7) K. Spin lattice (T1) measurements reveal an essentially gapless excitation spectrum with a maximum gap Δ/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 V4+ ions in the breathing kagome planes to the interlayer V3+ (S=1) spins.
Orain , J C , Bernu , B , Mendels , P , Clark , L , Aidoudi , F H , Lightfoot , P , Morris , R E & Bert , F 2017 , ' Nature of the spin liquid ground state in a breathing kagome compound studied by NMR and series expansion ' Physical Review Letters , vol 118 , no. 23 , 237203 . DOI: 10.1103/PhysRevLett.118.237203
Physical Review Letters
© 2017 American Physical Society. This work has been made available online in accordance with the publisher’s policies. This is the author created accepted version manuscript following peer review and as such may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1103/PhysRevLett.118.237203
This work was supported by the French Agence Nationale de la Recherche under Grant No. ANR-12-BS04-0021 “SPINLIQ.” J.-C. O. acknowledges support from the Region Ile de France through the DIM OxyMore. Work at the University of St. Andrews was supported by the Leverhulme Trust RPG-2013-343.
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