  The quest for nonmagnetic Weyl semimetals with high tunability of phase has
remained a demanding challenge. As the symmetry breaking control parameter, the
ferroelectric order can be steered to turn on/off the Weyl semimetals phase,
adjust the band structures around the Fermi level, and enlarge/shrink the
momentum separation of Weyl nodes which generate the Berry curvature as the
emergent magnetic field. Here, we report the realization of a ferroelectric
nonmagnetic Weyl semimetal based on indium doped Pb1 xSnxTe alloy where the
underlying inversion symmetry as well as mirror symmetry is broken with the
strength of ferroelectricity adjustable via tuning indium doping level and
Sn/Pb ratio. The transverse thermoelectric effect, i.e., Nernst effect both for
out of plane and in plane magnetic field geometry, is exploited as a Berry
curvature sensitive experimental probe to manifest the generation of Berry
curvature via the redistribution of Weyl nodes under magnetic fields. The
results demonstrate a clean non-magnetic Weyl semimetal coupled with highly
tunable ferroelectric order, providing an ideal platform for manipulating the
Weyl fermions in nonmagnetic system.
