  Broken symmetry is the essence of exotic properties in condensed matters.
Tungsten ditelluride, WTe$_2$, exceptionally takes a non-centrosymmetric
crystal structure in the family of transition metal dichalcogenides, and
exhibits novel properties$^{1-4}$, such as the nonsaturating
magnetoresistance$^1$ and ferroelectric-like behavior$^4$. Herein, using the
first-principles calculation, we show that unique layer stacking in WTe$_2$
generates surface dipoles with different strengths on the top and bottom
surfaces in few-layer WTe$_2$. This leads to a layer-dependence for
electron/hole carrier ratio and the carrier compensation responsible for the
unusual magnetoresistance. The surface dipoles are tunable and switchable using
the interlayer shear displacement. This could explain the ferroelectric-like
behavior recently observed in atomically thin WTe$_2$ films$^4$. In addition,
we reveal that exfoliation of the surface layer flips the out-of-plane spin
textures. The presented results will aid in the deeper understanding,
manipulation, and further exploration of the physical properties of WTe$_2$ and
related atom-layered materials, for applications in electronics and spintronic
devices.
