  180{\deg} domains walls (DWs) of Head-to-Head/Tail-to-Tail (H-H/T-T) type in
ferroelectric (FE) materials are of immense interest for a comprehensive
understanding of the FE attributes as well as harnessing them for new
applications. Our first principles calculation suggests that such DW formation
in Hafnium Zirconium Oxide (HZO) based FEs depends on the unique attributes of
the HZO unit cell, such as polar-spacer segmentation. Cross pattern of the
polar and spacer segments in two neighboring domains along the polarization
direction (where polar segment of one domain aligns with the spacer segment of
another) boosts the stability of such DWs. We further show that low density of
oxygen vacancies at the metal-HZO interface and high work function of metal
electrodes are conducive for T-T DW formation. On the other hand, high density
of oxygen vacancy and low work function of metal electrode favor H-H DW
formation. Polarization bound charges at the DW get screened when band bending
from depolarization field accumulates holes (electrons) in T-T (H-H) DW. For a
comprehensive understanding, we also investigate their FE nature and domain
growth mechanism. Our analysis suggests that a minimum thickness criterion of
domains has to be satisfied for the stability of H-H/T-T DW and switching of
the domains through such DW formation.
