Novel Quantum Spin Liquid States in the $S = {\frac{1}{2}}$ Three-Dimensional Compound Y$_{3}$Cu$_{2}$Sb$_{3}$O$_{14}$

Saikat Nandi; Rounak Das; M. Hemmida; M. U. Akbar; H. -A. Krug von Nidda; Jörg Sichelschmidt; Sagar Mahapatra; Marlis Schuller; N. Büttgen; John Wilkinson; M. P. Saravanan; Indra Dasgupta; A. V. Mahajan

doi:10.1103/2bps-xvl8

arXiv · 2509.15835

Novel Quantum Spin Liquid States in the $S = {\frac{1}{2}}$ Three-Dimensional Compound Y$_{3}$Cu$_{2}$Sb$_{3}$O$_{14}$

Saikat Nandi·Rounak Das·M. Hemmida·M. U. Akbar·H. -A. Krug von Nidda·Jörg Sichelschmidt·Sagar Mahapatra·Marlis Schuller·N. Büttgen·John Wilkinson·M. P. Saravanan·Indra Dasgupta·A. V. Mahajan

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Abstract

The three-dimensional $S = {\frac{1}{2}}$ system Y$_{3}$Cu$_{2}$Sb$_{3}$O$_{14}$ consists of two inequivalent Cu$^{2+}$ sites, each forming an edge shared triangular lattice. Our magnetic susceptibility $\chi(T)$, specific heat $C_p(T)$, $^{89}$Y nuclear magnetic resonance (NMR), muon spin relaxation ($\upmu\mathrm{SR}$), and electron spin resonance (ESR) measurements on this system confirm the absence of any long-range magnetic ordering and the persistence of spin dynamics down to 0.077 K. In $^{89}$Y NMR we find an anomaly at about 120 K which we suggest arises from a fraction of the spins condensing into a singlet (a valence bond solid VBS) state. A plateau in the muon relaxation rate is observed between 60 K and 10 K (signifying the VBS state from a fraction of the spins) followed by an increase and another plateau below about 1 K (presumably signifying the quantum spin liquid state from all the spins). Our density functional theory calculations find a dominant antiferromagnetic interaction along the body diagonal with inequivalent Cu(1) and Cu(2) ions alternately occupying the corners of the cube. All other near-neighbour interactions between the Cu ions are also found to be antiferromagnetic and are thought to drive the frustration.

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Saikat Nandi, Rounak Das, M. Hemmida, M. U. Akbar, H. -A. Krug von Nidda, Jörg Sichelschmidt, Sagar Mahapatra, Marlis Schuller, N. Büttgen, John Wilkinson, M. P. Saravanan, Indra Dasgupta, A. V. Mahajan. 2025-09-19. Novel Quantum Spin Liquid States in the $S = {\frac{1}{2}}$ Three-Dimensional Compound Y$_{3}$Cu$_{2}$Sb$_{3}$O$_{14}$. https://doi.org/10.1103/2bps-xvl8

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