Two-dimensional ferroelectricity and switchable spin-textures in ultra-thin elemental Te multilayers

Abstract

New ferroelectric materials with satisfactory performance at the nanoscale are critical for the ever-developing microelectronics industry. Here, we report two-dimensional (2D) ferroelectricity in elemental tellurium multilayers, which exhibit spontaneous in-plane polarization due to the interlayer interaction between lone pairs. The magnitude of the polarization reaches about 1.02 × 10⁻¹⁰ C m⁻¹ per layer, which can be detected by current experimental technology as recently done for the 2D FE compound SnTe. The spontaneous ferroelectric polarization can be preserved for the bilayer Te film even above room temperature. Also, we show that due to the strong spin–orbit coupling of Te, there appear nontrivial valley-dependent spin-textures for the hole carriers, and the textures are coupled with the direction of FE polarization, which is tunable by an external electric field. Our findings not only introduce the concept of ferroelectricity in elemental systems, but also broaden the family of the 2D ferroelectric materials and offer a promising platform for novel electronic and spintronic applications.