Silicene and germanene are key materials for the field of valleytronics. However, interaction with the substrate, which is necessary to support the electronically active medium, becomes a major obstacle. In the present work, we propose a substrate (F-doped WS_2) that avoids detrimental effects and at the same time induces the required valley polarization, so that no further steps are needed for this purpose. The behavior is explained by proximity effects on silicene/germanene, as demonstrated

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... first-principles calculations. Broken inversion symmetry due to the presence of WS_2 opens a substantial band gap in silicene/germanene. F doping of WS_2 results in spin polarization, which, in conjunction with proximity-enhanced spin orbit coupling, creates sizable spin-valley polarization.