  Polytypes of tetralayer graphene (TLG: Bernal, rhombohedral and mixed
stacking) are crystalline structures with different symmetries. Among those,
mixed-stacking tetralayers lack inversion symmetry, which allows for intrinsic
spontaneous out-of-plane electrical polarisation, inverted in the mirror-image
pair, ABCB and ABAC stackings. Here, we compare the intrinsic polarisation of
such TLGs with the symmetry-breaking effect of a substrate, which can also
generate out-of-plane electric dipole moments with different sizes in all four
polytypes, including ABCB and ABAC twins. We analyse their temperature and
magnetic field dependence, in view of understanding the origin of the recently
measured Kelvin probe force microscopy maps of tetralayer flakes, and notice
that the intrinsic contribution could be singled out based on magnetic field
dependence of polarisation measured at low temperatures.
