  The surfaces generated by cleaving non-polar, two-dimensional oxides are
often considered to be perfect or ideal. However, single particle
spectroscopies on Sr2RuO4, an archetypal non-polar two dimensional oxide, show
significant cleavage temperature dependence. We demonstrate that this is not a
consequence of the intrinsic characteristics of the surface: lattice parameters
and symmetries, step heights, atom positions, or density of states. Instead, we
find a marked increase in the density of defects at the mesoscopic scale with
increased cleave temperature. The potential generality of these defects to
oxide surfaces may have broad consequences to interfacial control and the
interpretation of surface sensitive measurements.
