We report the formation of a periodic supercrystal phase with hexagonal features and dimensions near 100 nm, in a supported phospholipid bilayer containing a mixture of the cationic DOTAP and the zwitterionic DSPC. Supercrystal phases with dimensions this small have never been seen in supported bilayer systems despite their relevance to raft formation in cellular structures. The formation, size, and separation of the hexagonal features were dependent on the cationic lipid concentration in the bilayer. These results indicate that small scale lipid domains may be stabilized by electrostatic repulsive forces.