In a post I made in the materials engineering sub forum someone mentioned the field extends only a few atomic spacings beyond the surface of a crystal, in the case where I was thinking a micro crystal grain. After talking to a physics lecturer he mentioned that due to the positive and negative charges from atoms and electrons that it is very plausible a field would be negated outside the bulk of the crystal. Wikipedia mentions that a P vector is varied by the surface charge density, but this is not the source of the piezoelectric effect but that the bulks dipole density is. Is there a type of piezo electric crystal that could have a field extend beyond the surface. And is this the case in electric lighters? There is some mention of poling in the wiki article, alignment of the weiss domains that form around dipoles.