High-throughput discovery of two-dimensional materials exhibiting strong Rashba-Edelstein effect

The Rashba-Edelstein effect (REE), which generates spin accumulation under an applied electric current, quantifies charge-to-spin conversion (CSC) efficiency in noncentrosymmetric systems. However, systematic investigations of REE in two-dimensional (2D) materials remain scarce. To address this gap, we perform a comprehensive symmetry analysis based on the 80 crystallographic layer groups, elucidating the relationship between materials' symmetries and the geometric characteristics of the REE response tensor. Our analysis identifies 13 distinct symmetry classes for the tensor and reveals all potential material candidates. Considering the requirement of strong spin-orbit coupling for a large REE response, we screen the C2DB database and identify 54 promising 2D materials. First-principles calculations demonstrate that the largest REE response coefficients in these materials exceed those reported for other 2D systems by an order of magnitude, indicating exceptionally high CSC efficiency. Focusing on three representative materials, including ${\mathrm{HgI}}_{2}, {\mathrm{AgTlP}}_{2}{\mathrm{Se}}_{6}$, and BrGaTe, we show that their large response coefficients can be well explained by effective $\mathbit{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbit{p}$ models and the characteristic spin textures around high-symmetry points in momentum space. This work provides a systematic framework and identifies high-performance candidates, paving the way for future exploration of REE-driven CSC in 2D materials.