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B Kim, S. Khmelevskyi, P. Mohn, C. Franchini:
"Competing magnetic interactions in a spin-1/2 square lattice: Hidden order in Sr₂VO₄";
Physical Review B, 96 (2017), 1804051 - 1804056.

With decreasing temperature, Sr2VO4 undergoes two structural phase transitions, tetragonal-to-orthorhombicto-
tetragonal, without long-range magnetic order. Recent experiments suggest that only at very low temperature,
Sr2VO4 might enter a yet-unknown phase with long-range magnetic order, but without orthorhombic distortion.
By combining relativistic density functional theory with an extended spin-1/2 compass-Heisenberg model, we
find an antiferromagnetic single-stripe ground state with highly competing exchange interactions, involving
a non-negligible interlayer coupling, which places the system at the crossover between the XY-model and
Heisenberg-model regimes. Most strikingly, we find a strong two-site "spin-compass" exchange anisotropy
which is relieved by the orthorhombic distortion induced by the spin stripe order. Based on these results, we
discuss the origin of the hidden-order phase and the possible formation of a spin liquid at low temperatures.