Proximity-induced spin-valley polarization in silicene or germanene on F-doped WS2

Abstract

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 or germanene, as demonstrated by first-principles calculations. Broken inversion symmetry due to the presence of WS 2 opens a substantial band gap in silicene or germanene. F doping of WS 2 results in spin polarization, which, in conjunction with proximity-enhanced spin-orbit coupling, creates sizable spin-valley polarization.

Effects of post-transfer annealing and substrate interactions on the photoluminescence of 2D/3D monolayer WS2/Ge heterostructures

“…A similar case with germanene, a 2D form of Ge, also revealed a reduction in the distance between interacting germanene and WS 2 layers. 53 Thus, it is possible that the enhanced interfacial interaction in WS 2 /Ge (100) can result in our experimentally observed PL quenching phenomenon. To verify this, we investigated the interfacial interaction and electronic behavior in the WS 2 /Ge(100) heterostructure.…”

Halogen Functionalization in the 2D Material Flatland: Strategies, Properties, and Applications

“…[ 208 ] The F‐doped WS 2 was proposed to generate a proximity effect to open a substantial spin‐polarized bandgap via time‐reversal symmetry breaking and induce spin‐valley polarization in silicene and germanene. [ 209 ] The impurity of Cl was calculated to reduce the n‐type Schottky barrier in the WS 2 and metal contacts. [ 210 ]…”

Progress on two-dimensional ferrovalley materials

“…The realization of the degeneracy of the valley is very beneficial to the development of valleytronics. Hence, researchers have gradually developed a series of methods to achieve valley polarization, such as magnetic atom doping, [11][12][13][14] magnetic proximity effect, [15][16][17][18][19] external magnetic fields, [20][21][22][23][24] and optical Stark effects. [9,10,25,26] It is worth noting that the valley polarization is achieved by the above means.…”