Generalized bloch theorem for spin spirals in abinit

Spin spirals are a special class of noncollinear magnetic configurations that can give rise to intriguing phenomena, including magnetoelectric coupling and ferroelectric polarization. While conventional supercell calculations of spin spirals are computationally demanding, the generalized Bloch theorem (GBT) allows them to be treated within the primitive unit cell in the absence of spin–orbit coupling (SOC). In this work, we present and validate the implementation of GBT in ABINIT, enabling self-consistent calculations of total energies, magnetic moments, stresses, forces, and electric polarization. The implementation is benchmarked against supercell calculations, finite-difference results, VASP calculations, and literature data for BCC and FCC Fe, MnF₂, and LiCu₂O₂. To account for SOC within the GBT framework, we employ a projected spin–orbit coupling (PSOC) approach, which is validated using Bi and a Co/Pt bilayer. We further demonstrate its applicability to magnetoelectric systems by investigating the electronic polarization of monolayer NiBr₂. This dataset contains the first-principles input and output files, pseudopotentials, and numerical results supporting the implementation and validation of GBT and PSOC for spin-spiral calculations in ABINIT.