Establish whether the single-spin-spiral state is the true ground state of TiFe6Ga6

Establish whether the approximately 135° single-spin-spiral state in TiFe6Ga6 is the true magnetic ground state, rather than a lower-energy configuration produced by longer-range bilinear or higher-order itinerant interactions.

Background

For TiFe6Ga6, single-spin-spiral calculations locate a low-energy minimum near a 135° rotation between every second transition-metal layer. However, this state is only about 0.5 meV per transition-metal atom below the AFM2 configuration, so the energy separation is too small to distinguish it reliably from competing states.

The authors explicitly note that additional magnetic configurations are needed to separate long-range bilinear exchange from higher-order itinerant terms. Although subsequent double-spin-spiral calculations identify a lower-energy sampled configuration with an additional rotation near 75°, the paper still treats the predicted magnetic structure as a candidate requiring experimental and broader theoretical validation.