Scanning Tunneling Microscopy Study of InP\(100\)-\(2×4\): An Exception to the Dimer Model

We report the first atomic resolution scanning tunneling microscopy images of the InP\(100\)-\(2×4\) surface. High resolution images were obtained for both occupied and unoccupied states. The ×4 periodicity is due to missing rows, and the ×2 periodicity to the repetition of what appear to be trimer units. It is demonstrated that the images are inconsistent with dimer-based models proposed for related semiconductor surfaces such as GaAs.