  Efficient generation and manipulation of spin signals in a given material
without invoking external magnetism remain one of the challenges in
spintronics. The spin Hall effect (SHE) and Rashba-Edelstein effect (REE) are
well-known mechanisms to electrically generate spin accumulation in materials
with strong spin-orbit coupling (SOC), but the exact role of the strength and
type of SOC, especially in crystals with low symmetry, has yet to be explained.
In this study, we investigate REE in two different families of non-magnetic
chiral materials, elemental semiconductors (Te and Se) and semimetallic
disilicides (TaSi$_2$ and NbSi$_2$), using an approach based on density
functional theory (DFT). By analyzing spin textures across the full Brillouin
zones and comparing them with REE magnitudes calculated as a function of
chemical potential, we link specific features in the electronic structure with
the efficiency of the induced spin accumulation. Our findings show that
magnitudes of REE can be increased by: (i) the presence of purely radial
(Weyl-type) spin texture manifesting as the parallel spin-momentum locking,
(ii) high spin polarization of bands along one specific crystallographic
direction, (iii) low band velocities. By comparing materials possessing the
same crystal structures, but different strengths of SOC, we conclude that
larger SOC may indirectly contribute to the enhancement of REE. It yields
greater spin-splitting of bands along specific crystallographic directions,
which prevents canceling the contributions from the oppositely spin-polarized
bands over wider energy regions and helps maintain larger REE magnitudes. We
believe that these results will be useful for designing spintronics devices and
may aid further computational studies searching for efficient REE in materials
with different symmetries and SOC strengths.

Materials Science;Computational Physics