  Ferroelectric nematic liquid crystals are formed by achiral molecules with
large dipole moments. Its three-dimensional orientational order is universally
described as unidirectionally polar. We demonstrate that the ground state of
ferroelectric nematic unconstrained by externally imposed alignment directions
is chiral, with left- and right-hand twists of polarization. Although the
helicoidal deformations and defect walls separating domains of opposite
handedness increase the elastic energy, the twists reduce the electrostatic
energy and become weaker when the material is doped with ions. The study shows
that the polar orientational order of molecules could trigger chirality in the
soft matter with no chemically induced chiral centers.
