  2D Ferroelectricity with switchable electric polarization has drawn
widespread attention in condensed matter physics due to its crucial
applications in non-volatile memory and ferroelectric spin devices. Despite
recent progress in 2D ferroelectric, achieving the mono-elemental
ferroelectricity still remains a great challenge because most nonmetallic
mono-elemental materials are stabilized in nonpolar crystal structures. In this
work, we theoretically designed mono-elemental ferroelectricity with tunable
and significant spin textures in bilayer tellurium (BL-Te). Comprehensive
quantitative polarization calculations demonstrate that asymmetric stacking in
BL-Te can generate out-of-plane (OOP) polarization with a magnitude of 0.78
pC/m. This polarization stems from distinguishing interlayer and intra-layer
contributions. Moreover, these stacked BL-Te, characterized by significant
spin-orbit coupling, serve as an ideal platform for investigating both
conventional spin polarization and layer-dependent/hidden spin polarization
through ferroelectric reversion. Our work not only broaden the category of 2D
mono-elemental ferroelectric but also offer a new platform for multifunctional
nanodevices.
