Controllable charge-spin conversion in sliding multiferroic metal Fe3GaTe2

Overview & Synopsis

Controlling charge--spin conversion within a single magnetic material is important for compact spintronic devices. Using first-principles calculations, symmetry analysis, and Wannier-based linear response, we study the Edelstein and spin Hall responses of sliding-ferroelectric bilayer \ce{Fe3GaTe2}. Two degenerate ground states with opposite interlayer sliding vectors and out-of-plane dipole moments are separated by a calculated switching barrier of about $16.3$~meV per unit cell. Magnetization orientation determines the allowed current-induced spin components, while ferroelectric switching induces component-selective sign reversals governed by $M_z\mathcal T$ for in-plane magnetization and by $M_z$ for out-of-plane magnetization. The Edelstein response is strongly energy dependent, with spin accumulation approaching $2~\hbar$ for $\mathbf m\parallel+y$ under a reference field of $1$~V/Å. Momentum-resolved analysis links the TR-even and TR-odd Edelstein responses to $Γ$-centered constant-energy contours and localized interband features, respectively. Spin-conductivity contributions show the opposite momentum-space character, with broad sign-competing spin Berry curvature for TR-even and narrow Fermi-surface contours for TR-odd. The transverse spin Hall conductivity reaches $\sim10^{3}\,(\hbar/e)(\mathrm{S/cm})$ and depends strongly on ferroelectric state and magnetization direction. Magnetization rotations in the $xy$ and $xz$ planes reveal symmetry-allowed higher angular harmonics in both spin accumulation and spin-current responses. These results establish sliding-ferroelectric bilayer \ce{Fe3GaTe2} as a tunable platform for reconfigurable spin accumulation and spin-current generation.