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Polar crystals composed of charged ionic planes cannot exist in nature without acquiring surface changes to balance an ever-growing dipole. The necessary changes can manifest structurally or electronically as observed in semiconductors and ferroelectric materials through screening charges and/or domain wall formation. In the case of prototypical polar complex oxides such as the system the nature of screening charges for different interface terminations is not symmetric. Electron accumulation is observed near the interface, while the /SrO- stack is insulating. Here, we observe evidence for an asymmetry in the surface chemical termination for nominally stoichiometric films in contact with the two different surface layers of crystals, and SrO. Using several element-specific probes, we find that the surface termination of remains irrespective of the starting …