| Summary: | 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 (2D) ferroelectric
bilayer WTe2. Due to the low symmetry of the crystal (Cs 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 2D materials, offering a promising platform
for highly efficient and non-volatile spintronic devices
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