Weak three-dimensional coupling of Heisenberg quantum spin chains in SrCuTe2O6

The magnetic Hamiltonian of the Heisenberg quantum antiferromagnet SrCuTe2O6 is studied by inelastic neutron scattering technique on powder and single-crystalline samples above and below the magnetic transition temperatures at 8 and 2 K. The high-temperature spectra reveal a characteristic diffuse scattering corresponding to a multispinon continuum, confirming the dominant quantum spin chain behavior due to the third neighbor interaction J(intra) = 4.22 meV (49 K). The low-temperature spectra exhibit sharper excitations at energies <1.25 meV, which can be explained by considering a combination of weak antiferromagnetic first nearest neighbor interchain coupling J(1) = 0.17 meV (1.9 K) and even weaker ferromagnetic second nearest neighbor 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 SrCuTe2O6 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 isostructural quantum spin liquid candidate PbCuTe2O6.

Automated summary

The study used inelastic neutron scattering technique to investigate the magnetic Hamiltonian of the Heisenberg quantum antiferromagnet SrCuTe2O6. Different behaviors were observed above and below the magnetic transition temperatures, revealing a unique one-dimensional nature of the material. The results suggest that SrCuTe2O6 has a highly one-dimensional Heisenberg system with complex coupling interactions, presenting a scenario different from other related materials.