Reversible canted persistent spin textures with large spin splitting in two-dimensional ferroelectric bilayer WTe$_{2}$

TL;DR

This paper reports the discovery of a reversible, stable persistent spin texture with large spin splitting in 2D ferroelectric bilayer WTe2, tunable by electric field and ferroelectric switching, advancing spintronics applications.

Contribution

It demonstrates the emergence of a robust, reversible PST with large spin splitting in 2D ferroelectric WTe2, enabled by symmetry breaking and electric field control, which was not previously known.

Findings

Stable PST with large spin splitting observed in bilayer WTe2.

Reversible PST achieved through ferroelectric switching and external electric field.

Potential for electrically tunable spintronic devices in 2D materials.

Abstract

The recent discovery of materials hosting persistent spin texture (PST) opens an avenue for the realization of energy-saving spintronics since they support an extraordinarily long spin lifetime. However, the stability of the PST is sensitively affected by symmetry breaking of the crystal induced by external perturbation such as the electric field. In this paper, through first-principles calculations supplemented by symmetry analysis, we report the emergence of the robust and stable PST with large spin splitting in the two-dimensional ferroelectric bilayer WTe$_{2}$. Due to the low symmetry of the crystal ($C_{s}$ point group), we observe a canted PST in the spin-split bands around the Fermi level displaying a unidirectional spin configuration tilted along the $yz$ plane in the first Brillouin zone. Such a typical PST can be effectively reversed by out-of-plane ferroelectric switching induced by interlayer sliding along the in-plane direction. We further demonstrated that the reversible PST is realized by the application of an out-of-plane external electric field. Thus, our findings uncover the possibility of an electrically tunable PST in the 2D materials, offering a promising platform for highly efficient spintronics devices.