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arXiv · 2107.05331

Weak three-dimensional coupling of Heisenberg quantum spin chains in SrCuTe$_{2}$O$_{6}$

S. Chillal·A. T. M. N. Islam·P. Steffens·R. Bewley·B. Lake
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Abstract

The magnetic Hamiltonian of the Heisenberg quantum antiferromagnet SrCuTe$_{2}$O$_{6}$ is studied by inelastic neutron scattering technique on powder and single crystalline samples above and below the magnetic transition temperatures at 8 K and 2 K. The high temperature spectra reveal a characteristic diffuse scattering corresponding to a multi-spinon continuum confirming the dominant quantum spin-chain behavior due to the third neighbour interaction J$_{intra}$ = 4.22 meV (49 K). The low temperature spectra exhibits sharper excitations at energies below 1.25 meV which can be explained by considering a combination of weak antiferromagnetic first nearest neighbour interchain coupling J$_1$ = 0.17 meV (1.9 K) and even weaker ferromagnetic second nearest neighbour J$_2$ = -0.037 meV (-0.4 K) or a weak ferromagnetic J$_2$ = -0.11 meV (-1.3 K) and antiferromagnetic J$_6$ = 0.16 meV (1.85 K) giving rise to the long-range magnetic order and spin-wave excitations at low energies. These results suggest that SrCuTe$_{2}$O$_{6}$ is a highly one-dimensional Heisenberg system with three mutually perpendicular spin-chains coupled by a weak ferromagnetic J$_2$ in addition to the antiferromagnetic J$_1$ or J$_6$ presenting a contrasting scenario from the highly frustrated hyper-hyperkagome lattice (equally strong antiferromagnetic J$_1$ and J$_2$) found in the iso-structural PbCuTe$_{2}$O$_{6}$.

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S. Chillal, A. T. M. N. Islam, P. Steffens, R. Bewley, B. Lake. 2021-07-16. Weak three-dimensional coupling of Heisenberg quantum spin chains in SrCuTe$_{2}$O$_{6}$. https://doi.org/10.1103/physrevb.104.144402

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